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  • How can I tell if I'm behind a portal or proxy

    - by user19269
    I'm testing out a Content management system on my computer and have emailed their support for a problem regarding login.. They've replied back and asked if my CMS is behind a portal or proxy. I feel kind of stupid for not knowing this, but how do I find out? Everything is local (eg, hosted on my computer, etc). Thanks in advance!

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  • Better way to do "echo $x | sed ..." and "echo $x | grep ..."

    - by DevSolar
    I often find this in scripts (and, I have to admit, write it myself): a=`echo $x | sed "s/foo/bar/"` or if echo $x | grep foo then ... fi Consider "foo" to include some regex stuff. I feel that there should be - and most likely is - a better way to phrase this, one that does not involve two commands and a pipe but wraps the thing into some more compact expression. I just can't find it. Anybody?

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  • Quick method to determine SSD drive health?

    - by ewwhite
    I have an Intel X-25M drive that was marked "failed" twice in a ZFS storage array, as noted here. However, after removing the drive, it seems to to mount, read and write in other computers (Mac, PC, USB enclosure, etc.) Is there a good way to determine the drive's present health? I feel that the previous failure in the ZFS solution was the convergence of bugs, bad error reporting and hardware. It seems like this drive may have some life in it, though.

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  • mysql cluster problem in ubuntu

    - by Firman
    I have a problem while installing and configuring mysql cluster runnign on ubuntu 10.10 This is configuration for Cluster management [NDBD DEFAULT] NoOfReplicas=2 DataMemory=10MB IndexMemory=25MB MaxNoOfTables=256 MaxNoOfOrderedIndexes=256 MaxNoOfUniqueHashIndexes=128 [MYSQLD DEFAULT] [NDB_MGMD DEFAULT] [TCP DEFAULT] [NDB_MGMD] Id=1 # the NDB Management Node (this one) HostName=192.168.10.101 [NDBD] Id=2 # the first NDB Data Node HostName=192.168.10.11 DataDir= /var/lib/mysql-cluster [NDBD] Id=3 # the second NDB Data Node HostName=192.168.10.12 DataDir=/var/lib/mysql-cluster [MYSQLD] [MYSQLD] and this is configuration for both node : [mysqld] ndbcluster ndb-connectstring=192.168.10.101 # the IP of the MANAGMENT (THIRD) SERVER [mysql_cluster] ndb-connectstring=192.168.10.101 # the IP of the MANAGMENT (THIRD) SERVER After running all node and management, and I use ndb_mgm, the type 'show' command, and something appear like this : ndb_mgm> show Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=2 @192.168.10.11 (mysql-5.1.39 ndb-7.0.9, Nodegroup: 0, Master) id=3 @192.168.10.12 (mysql-5.1.39 ndb-7.0.9, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 @192.168.10.101 (mysql-5.1.39 ndb-7.0.9) [mysqld(API)] 1 node(s) id=4 (not connected, accepting connect from 192.168.10.101) look at two last line.. not as what http://dev.mysql.com/tech-resources/articles/mysql-cluster-for-two-servers.html look like (see at point 4) anyone have ever had this problem ?

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  • Finding Font Issues in Acrobat

    - by Jayme
    Ok let me try this again, so sorry for not be clear. We create our PDFs through Quark, then send to print. I usually create outlines on my EPS files before I load in Quark but forgot this time. We bypassed the font error that Quark gave us by accident and found out our PDF was bad too late and it cost a lot of money to fix. We are trying to find a way to check our PDF for font problems before we send it to print, in case this problem happens again. We just want to be extra sure that we have tried everything. What I see in Quark is what the font is supposed to look like. When I view my PDF, the text is mixed up. Its readable but doesn't look like its supposed to and the spacing is all off within the text. My boss told me about the preflight in Quark and the Internal Structure for the fonts. She was asking me if this would help and what the lingo all meant. (which is where my first question started) The image on the left is my EPS that is correct, the image on the right is from the PDF. The white text in the top right and the website at the bottom left is what is messed up. I am running Mac 10.5.8, Quark 7.5 and Acrobat 8.3.1. Thanks, Jayme

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  • Need Advice on Server configuration

    - by user45324
    I have lab of 80 computer in my school. I need to run terminal server on each pc using remote desktop service of Microsoft server 2003. I need to run applications like Java, .NET, wamp, turbo c and other low memory applications like ms office and internet. so, could you please recommended some configuration for Mother Board and Processor. If you need any other information feel free to ask.

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  • SQLite, python, unicode, and non-utf data

    - by Nathan Spears
    I started by trying to store strings in sqlite using python, and got the message: sqlite3.ProgrammingError: You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings. Ok, I switched to Unicode strings. Then I started getting the message: sqlite3.OperationalError: Could not decode to UTF-8 column 'tag_artist' with text 'Sigur Rós' when trying to retrieve data from the db. More research and I started encoding it in utf8, but then 'Sigur Rós' starts looking like 'Sigur Rós' note: My console was set to display in 'latin_1' as @John Machin pointed out. What gives? After reading this, describing exactly the same situation I'm in, it seems as if the advice is to ignore the other advice and use 8-bit bytestrings after all. I didn't know much about unicode and utf before I started this process. I've learned quite a bit in the last couple hours, but I'm still ignorant of whether there is a way to correctly convert 'ó' from latin-1 to utf-8 and not mangle it. If there isn't, why would sqlite 'highly recommend' I switch my application to unicode strings? I'm going to update this question with a summary and some example code of everything I've learned in the last 24 hours so that someone in my shoes can have an easy(er) guide. If the information I post is wrong or misleading in any way please tell me and I'll update, or one of you senior guys can update. Summary of answers Let me first state the goal as I understand it. The goal in processing various encodings, if you are trying to convert between them, is to understand what your source encoding is, then convert it to unicode using that source encoding, then convert it to your desired encoding. Unicode is a base and encodings are mappings of subsets of that base. utf_8 has room for every character in unicode, but because they aren't in the same place as, for instance, latin_1, a string encoded in utf_8 and sent to a latin_1 console will not look the way you expect. In python the process of getting to unicode and into another encoding looks like: str.decode('source_encoding').encode('desired_encoding') or if the str is already in unicode str.encode('desired_encoding') For sqlite I didn't actually want to encode it again, I wanted to decode it and leave it in unicode format. Here are four things you might need to be aware of as you try to work with unicode and encodings in python. The encoding of the string you want to work with, and the encoding you want to get it to. The system encoding. The console encoding. The encoding of the source file Elaboration: (1) When you read a string from a source, it must have some encoding, like latin_1 or utf_8. In my case, I'm getting strings from filenames, so unfortunately, I could be getting any kind of encoding. Windows XP uses UCS-2 (a Unicode system) as its native string type, which seems like cheating to me. Fortunately for me, the characters in most filenames are not going to be made up of more than one source encoding type, and I think all of mine were either completely latin_1, completely utf_8, or just plain ascii (which is a subset of both of those). So I just read them and decoded them as if they were still in latin_1 or utf_8. It's possible, though, that you could have latin_1 and utf_8 and whatever other characters mixed together in a filename on Windows. Sometimes those characters can show up as boxes, other times they just look mangled, and other times they look correct (accented characters and whatnot). Moving on. (2) Python has a default system encoding that gets set when python starts and can't be changed during runtime. See here for details. Dirty summary ... well here's the file I added: \# sitecustomize.py \# this file can be anywhere in your Python path, \# but it usually goes in ${pythondir}/lib/site-packages/ import sys sys.setdefaultencoding('utf_8') This system encoding is the one that gets used when you use the unicode("str") function without any other encoding parameters. To say that another way, python tries to decode "str" to unicode based on the default system encoding. (3) If you're using IDLE or the command-line python, I think that your console will display according to the default system encoding. I am using pydev with eclipse for some reason, so I had to go into my project settings, edit the launch configuration properties of my test script, go to the Common tab, and change the console from latin-1 to utf-8 so that I could visually confirm what I was doing was working. (4) If you want to have some test strings, eg test_str = "ó" in your source code, then you will have to tell python what kind of encoding you are using in that file. (FYI: when I mistyped an encoding I had to ctrl-Z because my file became unreadable.) This is easily accomplished by putting a line like so at the top of your source code file: # -*- coding: utf_8 -*- If you don't have this information, python attempts to parse your code as ascii by default, and so: SyntaxError: Non-ASCII character '\xf3' in file _redacted_ on line 81, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details Once your program is working correctly, or, if you aren't using python's console or any other console to look at output, then you will probably really only care about #1 on the list. System default and console encoding are not that important unless you need to look at output and/or you are using the builtin unicode() function (without any encoding parameters) instead of the string.decode() function. I wrote a demo function I will paste into the bottom of this gigantic mess that I hope correctly demonstrates the items in my list. Here is some of the output when I run the character 'ó' through the demo function, showing how various methods react to the character as input. My system encoding and console output are both set to utf_8 for this run: '?' = original char <type 'str'> repr(char)='\xf3' '?' = unicode(char) ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data 'ó' = char.decode('latin_1') <type 'unicode'> repr(char.decode('latin_1'))=u'\xf3' '?' = char.decode('utf_8') ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data Now I will change the system and console encoding to latin_1, and I get this output for the same input: 'ó' = original char <type 'str'> repr(char)='\xf3' 'ó' = unicode(char) <type 'unicode'> repr(unicode(char))=u'\xf3' 'ó' = char.decode('latin_1') <type 'unicode'> repr(char.decode('latin_1'))=u'\xf3' '?' = char.decode('utf_8') ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data Notice that the 'original' character displays correctly and the builtin unicode() function works now. Now I change my console output back to utf_8. '?' = original char <type 'str'> repr(char)='\xf3' '?' = unicode(char) <type 'unicode'> repr(unicode(char))=u'\xf3' '?' = char.decode('latin_1') <type 'unicode'> repr(char.decode('latin_1'))=u'\xf3' '?' = char.decode('utf_8') ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data Here everything still works the same as last time but the console can't display the output correctly. Etc. The function below also displays more information that this and hopefully would help someone figure out where the gap in their understanding is. I know all this information is in other places and more thoroughly dealt with there, but I hope that this would be a good kickoff point for someone trying to get coding with python and/or sqlite. Ideas are great but sometimes source code can save you a day or two of trying to figure out what functions do what. Disclaimers: I'm no encoding expert, I put this together to help my own understanding. I kept building on it when I should have probably started passing functions as arguments to avoid so much redundant code, so if I can I'll make it more concise. Also, utf_8 and latin_1 are by no means the only encoding schemes, they are just the two I was playing around with because I think they handle everything I need. Add your own encoding schemes to the demo function and test your own input. One more thing: there are apparently crazy application developers making life difficult in Windows. #!/usr/bin/env python # -*- coding: utf_8 -*- import os import sys def encodingDemo(str): validStrings = () try: print "str =",str,"{0} repr(str) = {1}".format(type(str), repr(str)) validStrings += ((str,""),) except UnicodeEncodeError as ude: print "Couldn't print the str itself because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t", print ude try: x = unicode(str) print "unicode(str) = ",x validStrings+= ((x, " decoded into unicode by the default system encoding"),) except UnicodeDecodeError as ude: print "ERROR. unicode(str) couldn't decode the string because the system encoding is set to an encoding that doesn't understand some character in the string." print "\tThe system encoding is set to {0}. See error:\n\t".format(sys.getdefaultencoding()), print ude except UnicodeEncodeError as uee: print "ERROR. Couldn't print the unicode(str) because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t", print uee try: x = str.decode('latin_1') print "str.decode('latin_1') =",x validStrings+= ((x, " decoded with latin_1 into unicode"),) try: print "str.decode('latin_1').encode('utf_8') =",str.decode('latin_1').encode('utf_8') validStrings+= ((x, " decoded with latin_1 into unicode and encoded into utf_8"),) except UnicodeDecodeError as ude: print "The string was decoded into unicode using the latin_1 encoding, but couldn't be encoded into utf_8. See error:\n\t", print ude except UnicodeDecodeError as ude: print "Something didn't work, probably because the string wasn't latin_1 encoded. See error:\n\t", print ude except UnicodeEncodeError as uee: print "ERROR. Couldn't print the str.decode('latin_1') because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t", print uee try: x = str.decode('utf_8') print "str.decode('utf_8') =",x validStrings+= ((x, " decoded with utf_8 into unicode"),) try: print "str.decode('utf_8').encode('latin_1') =",str.decode('utf_8').encode('latin_1') except UnicodeDecodeError as ude: print "str.decode('utf_8').encode('latin_1') didn't work. The string was decoded into unicode using the utf_8 encoding, but couldn't be encoded into latin_1. See error:\n\t", validStrings+= ((x, " decoded with utf_8 into unicode and encoded into latin_1"),) print ude except UnicodeDecodeError as ude: print "str.decode('utf_8') didn't work, probably because the string wasn't utf_8 encoded. See error:\n\t", print ude except UnicodeEncodeError as uee: print "ERROR. Couldn't print the str.decode('utf_8') because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t",uee print print "Printing information about each character in the original string." for char in str: try: print "\t'" + char + "' = original char {0} repr(char)={1}".format(type(char), repr(char)) except UnicodeDecodeError as ude: print "\t'?' = original char {0} repr(char)={1} ERROR PRINTING: {2}".format(type(char), repr(char), ude) except UnicodeEncodeError as uee: print "\t'?' = original char {0} repr(char)={1} ERROR PRINTING: {2}".format(type(char), repr(char), uee) print uee try: x = unicode(char) print "\t'" + x + "' = unicode(char) {1} repr(unicode(char))={2}".format(x, type(x), repr(x)) except UnicodeDecodeError as ude: print "\t'?' = unicode(char) ERROR: {0}".format(ude) except UnicodeEncodeError as uee: print "\t'?' = unicode(char) {0} repr(char)={1} ERROR PRINTING: {2}".format(type(x), repr(x), uee) try: x = char.decode('latin_1') print "\t'" + x + "' = char.decode('latin_1') {1} repr(char.decode('latin_1'))={2}".format(x, type(x), repr(x)) except UnicodeDecodeError as ude: print "\t'?' = char.decode('latin_1') ERROR: {0}".format(ude) except UnicodeEncodeError as uee: print "\t'?' = char.decode('latin_1') {0} repr(char)={1} ERROR PRINTING: {2}".format(type(x), repr(x), uee) try: x = char.decode('utf_8') print "\t'" + x + "' = char.decode('utf_8') {1} repr(char.decode('utf_8'))={2}".format(x, type(x), repr(x)) except UnicodeDecodeError as ude: print "\t'?' = char.decode('utf_8') ERROR: {0}".format(ude) except UnicodeEncodeError as uee: print "\t'?' = char.decode('utf_8') {0} repr(char)={1} ERROR PRINTING: {2}".format(type(x), repr(x), uee) print x = 'ó' encodingDemo(x) Much thanks for the answers below and especially to @John Machin for answering so thoroughly.

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  • SQLite, python, unicode, and non-utf data

    - by Nathan Spears
    I started by trying to store strings in sqlite using python, and got the message: sqlite3.ProgrammingError: You must not use 8-bit bytestrings unless you use a text_factory that can interpret 8-bit bytestrings (like text_factory = str). It is highly recommended that you instead just switch your application to Unicode strings. Ok, I switched to Unicode strings. Then I started getting the message: sqlite3.OperationalError: Could not decode to UTF-8 column 'tag_artist' with text 'Sigur Rós' when trying to retrieve data from the db. More research and I started encoding it in utf8, but then 'Sigur Rós' starts looking like 'Sigur Rós' note: My console was set to display in 'latin_1' as @John Machin pointed out. What gives? After reading this, describing exactly the same situation I'm in, it seems as if the advice is to ignore the other advice and use 8-bit bytestrings after all. I didn't know much about unicode and utf before I started this process. I've learned quite a bit in the last couple hours, but I'm still ignorant of whether there is a way to correctly convert 'ó' from latin-1 to utf-8 and not mangle it. If there isn't, why would sqlite 'highly recommend' I switch my application to unicode strings? I'm going to update this question with a summary and some example code of everything I've learned in the last 24 hours so that someone in my shoes can have an easy(er) guide. If the information I post is wrong or misleading in any way please tell me and I'll update, or one of you senior guys can update. Summary of answers Let me first state the goal as I understand it. The goal in processing various encodings, if you are trying to convert between them, is to understand what your source encoding is, then convert it to unicode using that source encoding, then convert it to your desired encoding. Unicode is a base and encodings are mappings of subsets of that base. utf_8 has room for every character in unicode, but because they aren't in the same place as, for instance, latin_1, a string encoded in utf_8 and sent to a latin_1 console will not look the way you expect. In python the process of getting to unicode and into another encoding looks like: str.decode('source_encoding').encode('desired_encoding') or if the str is already in unicode str.encode('desired_encoding') For sqlite I didn't actually want to encode it again, I wanted to decode it and leave it in unicode format. Here are four things you might need to be aware of as you try to work with unicode and encodings in python. The encoding of the string you want to work with, and the encoding you want to get it to. The system encoding. The console encoding. The encoding of the source file Elaboration: (1) When you read a string from a source, it must have some encoding, like latin_1 or utf_8. In my case, I'm getting strings from filenames, so unfortunately, I could be getting any kind of encoding. Windows XP uses UCS-2 (a Unicode system) as its native string type, which seems like cheating to me. Fortunately for me, the characters in most filenames are not going to be made up of more than one source encoding type, and I think all of mine were either completely latin_1, completely utf_8, or just plain ascii (which is a subset of both of those). So I just read them and decoded them as if they were still in latin_1 or utf_8. It's possible, though, that you could have latin_1 and utf_8 and whatever other characters mixed together in a filename on Windows. Sometimes those characters can show up as boxes, other times they just look mangled, and other times they look correct (accented characters and whatnot). Moving on. (2) Python has a default system encoding that gets set when python starts and can't be changed during runtime. See here for details. Dirty summary ... well here's the file I added: \# sitecustomize.py \# this file can be anywhere in your Python path, \# but it usually goes in ${pythondir}/lib/site-packages/ import sys sys.setdefaultencoding('utf_8') This system encoding is the one that gets used when you use the unicode("str") function without any other encoding parameters. To say that another way, python tries to decode "str" to unicode based on the default system encoding. (3) If you're using IDLE or the command-line python, I think that your console will display according to the default system encoding. I am using pydev with eclipse for some reason, so I had to go into my project settings, edit the launch configuration properties of my test script, go to the Common tab, and change the console from latin-1 to utf-8 so that I could visually confirm what I was doing was working. (4) If you want to have some test strings, eg test_str = "ó" in your source code, then you will have to tell python what kind of encoding you are using in that file. (FYI: when I mistyped an encoding I had to ctrl-Z because my file became unreadable.) This is easily accomplished by putting a line like so at the top of your source code file: # -*- coding: utf_8 -*- If you don't have this information, python attempts to parse your code as ascii by default, and so: SyntaxError: Non-ASCII character '\xf3' in file _redacted_ on line 81, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details Once your program is working correctly, or, if you aren't using python's console or any other console to look at output, then you will probably really only care about #1 on the list. System default and console encoding are not that important unless you need to look at output and/or you are using the builtin unicode() function (without any encoding parameters) instead of the string.decode() function. I wrote a demo function I will paste into the bottom of this gigantic mess that I hope correctly demonstrates the items in my list. Here is some of the output when I run the character 'ó' through the demo function, showing how various methods react to the character as input. My system encoding and console output are both set to utf_8 for this run: '?' = original char <type 'str'> repr(char)='\xf3' '?' = unicode(char) ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data 'ó' = char.decode('latin_1') <type 'unicode'> repr(char.decode('latin_1'))=u'\xf3' '?' = char.decode('utf_8') ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data Now I will change the system and console encoding to latin_1, and I get this output for the same input: 'ó' = original char <type 'str'> repr(char)='\xf3' 'ó' = unicode(char) <type 'unicode'> repr(unicode(char))=u'\xf3' 'ó' = char.decode('latin_1') <type 'unicode'> repr(char.decode('latin_1'))=u'\xf3' '?' = char.decode('utf_8') ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data Notice that the 'original' character displays correctly and the builtin unicode() function works now. Now I change my console output back to utf_8. '?' = original char <type 'str'> repr(char)='\xf3' '?' = unicode(char) <type 'unicode'> repr(unicode(char))=u'\xf3' '?' = char.decode('latin_1') <type 'unicode'> repr(char.decode('latin_1'))=u'\xf3' '?' = char.decode('utf_8') ERROR: 'utf8' codec can't decode byte 0xf3 in position 0: unexpected end of data Here everything still works the same as last time but the console can't display the output correctly. Etc. The function below also displays more information that this and hopefully would help someone figure out where the gap in their understanding is. I know all this information is in other places and more thoroughly dealt with there, but I hope that this would be a good kickoff point for someone trying to get coding with python and/or sqlite. Ideas are great but sometimes source code can save you a day or two of trying to figure out what functions do what. Disclaimers: I'm no encoding expert, I put this together to help my own understanding. I kept building on it when I should have probably started passing functions as arguments to avoid so much redundant code, so if I can I'll make it more concise. Also, utf_8 and latin_1 are by no means the only encoding schemes, they are just the two I was playing around with because I think they handle everything I need. Add your own encoding schemes to the demo function and test your own input. One more thing: there are apparently crazy application developers making life difficult in Windows. #!/usr/bin/env python # -*- coding: utf_8 -*- import os import sys def encodingDemo(str): validStrings = () try: print "str =",str,"{0} repr(str) = {1}".format(type(str), repr(str)) validStrings += ((str,""),) except UnicodeEncodeError as ude: print "Couldn't print the str itself because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t", print ude try: x = unicode(str) print "unicode(str) = ",x validStrings+= ((x, " decoded into unicode by the default system encoding"),) except UnicodeDecodeError as ude: print "ERROR. unicode(str) couldn't decode the string because the system encoding is set to an encoding that doesn't understand some character in the string." print "\tThe system encoding is set to {0}. See error:\n\t".format(sys.getdefaultencoding()), print ude except UnicodeEncodeError as uee: print "ERROR. Couldn't print the unicode(str) because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t", print uee try: x = str.decode('latin_1') print "str.decode('latin_1') =",x validStrings+= ((x, " decoded with latin_1 into unicode"),) try: print "str.decode('latin_1').encode('utf_8') =",str.decode('latin_1').encode('utf_8') validStrings+= ((x, " decoded with latin_1 into unicode and encoded into utf_8"),) except UnicodeDecodeError as ude: print "The string was decoded into unicode using the latin_1 encoding, but couldn't be encoded into utf_8. See error:\n\t", print ude except UnicodeDecodeError as ude: print "Something didn't work, probably because the string wasn't latin_1 encoded. See error:\n\t", print ude except UnicodeEncodeError as uee: print "ERROR. Couldn't print the str.decode('latin_1') because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t", print uee try: x = str.decode('utf_8') print "str.decode('utf_8') =",x validStrings+= ((x, " decoded with utf_8 into unicode"),) try: print "str.decode('utf_8').encode('latin_1') =",str.decode('utf_8').encode('latin_1') except UnicodeDecodeError as ude: print "str.decode('utf_8').encode('latin_1') didn't work. The string was decoded into unicode using the utf_8 encoding, but couldn't be encoded into latin_1. See error:\n\t", validStrings+= ((x, " decoded with utf_8 into unicode and encoded into latin_1"),) print ude except UnicodeDecodeError as ude: print "str.decode('utf_8') didn't work, probably because the string wasn't utf_8 encoded. See error:\n\t", print ude except UnicodeEncodeError as uee: print "ERROR. Couldn't print the str.decode('utf_8') because the console is set to an encoding that doesn't understand some character in the string. See error:\n\t",uee print print "Printing information about each character in the original string." for char in str: try: print "\t'" + char + "' = original char {0} repr(char)={1}".format(type(char), repr(char)) except UnicodeDecodeError as ude: print "\t'?' = original char {0} repr(char)={1} ERROR PRINTING: {2}".format(type(char), repr(char), ude) except UnicodeEncodeError as uee: print "\t'?' = original char {0} repr(char)={1} ERROR PRINTING: {2}".format(type(char), repr(char), uee) print uee try: x = unicode(char) print "\t'" + x + "' = unicode(char) {1} repr(unicode(char))={2}".format(x, type(x), repr(x)) except UnicodeDecodeError as ude: print "\t'?' = unicode(char) ERROR: {0}".format(ude) except UnicodeEncodeError as uee: print "\t'?' = unicode(char) {0} repr(char)={1} ERROR PRINTING: {2}".format(type(x), repr(x), uee) try: x = char.decode('latin_1') print "\t'" + x + "' = char.decode('latin_1') {1} repr(char.decode('latin_1'))={2}".format(x, type(x), repr(x)) except UnicodeDecodeError as ude: print "\t'?' = char.decode('latin_1') ERROR: {0}".format(ude) except UnicodeEncodeError as uee: print "\t'?' = char.decode('latin_1') {0} repr(char)={1} ERROR PRINTING: {2}".format(type(x), repr(x), uee) try: x = char.decode('utf_8') print "\t'" + x + "' = char.decode('utf_8') {1} repr(char.decode('utf_8'))={2}".format(x, type(x), repr(x)) except UnicodeDecodeError as ude: print "\t'?' = char.decode('utf_8') ERROR: {0}".format(ude) except UnicodeEncodeError as uee: print "\t'?' = char.decode('utf_8') {0} repr(char)={1} ERROR PRINTING: {2}".format(type(x), repr(x), uee) print x = 'ó' encodingDemo(x) Much thanks for the answers below and especially to @John Machin for answering so thoroughly.

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  • OpenGL 3.x Assimp trouble implementing phong shading (normals?)

    - by Defcronyke
    I'm having trouble getting phong shading to look right. I'm pretty sure there's something wrong with either my OpenGL calls, or the way I'm loading my normals, but I guess it could be something else since 3D graphics and Assimp are both still very new to me. When trying to load .obj/.mtl files, the problems I'm seeing are: The models seem to be lit too intensely (less phong-style and more completely washed out, too bright). Faces that are lit seem to be lit equally all over (with the exception of a specular highlight showing only when the light source position is moved to be practically right on top of the model) Because of problems 1 and 2, spheres look very wrong: picture of sphere And things with larger faces look (less-noticeably) wrong too: picture of cube I could be wrong, but to me this doesn't look like proper phong shading. Here's the code that I think might be relevant (I can post more if necessary): file: assimpRenderer.cpp #include "assimpRenderer.hpp" namespace def { assimpRenderer::assimpRenderer(std::string modelFilename, float modelScale) { initSFML(); initOpenGL(); if (assImport(modelFilename)) // if modelFile loaded successfully { initScene(); mainLoop(modelScale); shutdownScene(); } shutdownOpenGL(); shutdownSFML(); } assimpRenderer::~assimpRenderer() { } void assimpRenderer::initSFML() { windowWidth = 800; windowHeight = 600; settings.majorVersion = 3; settings.minorVersion = 3; app = NULL; shader = NULL; app = new sf::Window(sf::VideoMode(windowWidth,windowHeight,32), "OpenGL 3.x Window", sf::Style::Default, settings); app->setFramerateLimit(240); app->setActive(); return; } void assimpRenderer::shutdownSFML() { delete app; return; } void assimpRenderer::initOpenGL() { GLenum err = glewInit(); if (GLEW_OK != err) { /* Problem: glewInit failed, something is seriously wrong. */ std::cerr << "Error: " << glewGetErrorString(err) << std::endl; } // check the OpenGL context version that's currently in use int glVersion[2] = {-1, -1}; glGetIntegerv(GL_MAJOR_VERSION, &glVersion[0]); // get the OpenGL Major version glGetIntegerv(GL_MINOR_VERSION, &glVersion[1]); // get the OpenGL Minor version std::cout << "Using OpenGL Version: " << glVersion[0] << "." << glVersion[1] << std::endl; return; } void assimpRenderer::shutdownOpenGL() { return; } void assimpRenderer::initScene() { // allocate heap space for VAOs, VBOs, and IBOs vaoID = new GLuint[scene->mNumMeshes]; vboID = new GLuint[scene->mNumMeshes*2]; iboID = new GLuint[scene->mNumMeshes]; glClearColor(0.4f, 0.6f, 0.9f, 0.0f); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glEnable(GL_CULL_FACE); shader = new Shader("shader.vert", "shader.frag"); projectionMatrix = glm::perspective(60.0f, (float)windowWidth / (float)windowHeight, 0.1f, 100.0f); rot = 0.0f; rotSpeed = 50.0f; faceIndex = 0; colorArrayA = NULL; colorArrayD = NULL; colorArrayS = NULL; normalArray = NULL; genVAOs(); return; } void assimpRenderer::shutdownScene() { delete [] iboID; delete [] vboID; delete [] vaoID; delete shader; } void assimpRenderer::renderScene(float modelScale) { sf::Time elapsedTime = clock.getElapsedTime(); clock.restart(); if (rot > 360.0f) rot = 0.0f; rot += rotSpeed * elapsedTime.asSeconds(); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); viewMatrix = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, -3.0f, -10.0f)); // move back a bit modelMatrix = glm::scale(glm::mat4(1.0f), glm::vec3(modelScale)); // scale model modelMatrix = glm::rotate(modelMatrix, rot, glm::vec3(0, 1, 0)); //modelMatrix = glm::rotate(modelMatrix, 25.0f, glm::vec3(0, 1, 0)); glm::vec3 lightPosition( 0.0f, -100.0f, 0.0f ); float lightPositionArray[3]; lightPositionArray[0] = lightPosition[0]; lightPositionArray[1] = lightPosition[1]; lightPositionArray[2] = lightPosition[2]; shader->bind(); int projectionMatrixLocation = glGetUniformLocation(shader->id(), "projectionMatrix"); int viewMatrixLocation = glGetUniformLocation(shader->id(), "viewMatrix"); int modelMatrixLocation = glGetUniformLocation(shader->id(), "modelMatrix"); int ambientLocation = glGetUniformLocation(shader->id(), "ambientColor"); int diffuseLocation = glGetUniformLocation(shader->id(), "diffuseColor"); int specularLocation = glGetUniformLocation(shader->id(), "specularColor"); int lightPositionLocation = glGetUniformLocation(shader->id(), "lightPosition"); int normalMatrixLocation = glGetUniformLocation(shader->id(), "normalMatrix"); glUniformMatrix4fv(projectionMatrixLocation, 1, GL_FALSE, &projectionMatrix[0][0]); glUniformMatrix4fv(viewMatrixLocation, 1, GL_FALSE, &viewMatrix[0][0]); glUniformMatrix4fv(modelMatrixLocation, 1, GL_FALSE, &modelMatrix[0][0]); glUniform3fv(lightPositionLocation, 1, lightPositionArray); for (unsigned int i = 0; i < scene->mNumMeshes; i++) { colorArrayA = new float[3]; colorArrayD = new float[3]; colorArrayS = new float[3]; material = scene->mMaterials[scene->mNumMaterials-1]; normalArray = new float[scene->mMeshes[i]->mNumVertices * 3]; unsigned int normalIndex = 0; for (unsigned int j = 0; j < scene->mMeshes[i]->mNumVertices * 3; j+=3, normalIndex++) { normalArray[j] = scene->mMeshes[i]->mNormals[normalIndex].x; // x normalArray[j+1] = scene->mMeshes[i]->mNormals[normalIndex].y; // y normalArray[j+2] = scene->mMeshes[i]->mNormals[normalIndex].z; // z } normalIndex = 0; glUniformMatrix3fv(normalMatrixLocation, 1, GL_FALSE, normalArray); aiColor3D ambient(0.0f, 0.0f, 0.0f); material->Get(AI_MATKEY_COLOR_AMBIENT, ambient); aiColor3D diffuse(0.0f, 0.0f, 0.0f); material->Get(AI_MATKEY_COLOR_DIFFUSE, diffuse); aiColor3D specular(0.0f, 0.0f, 0.0f); material->Get(AI_MATKEY_COLOR_SPECULAR, specular); colorArrayA[0] = ambient.r; colorArrayA[1] = ambient.g; colorArrayA[2] = ambient.b; colorArrayD[0] = diffuse.r; colorArrayD[1] = diffuse.g; colorArrayD[2] = diffuse.b; colorArrayS[0] = specular.r; colorArrayS[1] = specular.g; colorArrayS[2] = specular.b; // bind color for each mesh glUniform3fv(ambientLocation, 1, colorArrayA); glUniform3fv(diffuseLocation, 1, colorArrayD); glUniform3fv(specularLocation, 1, colorArrayS); // render all meshes glBindVertexArray(vaoID[i]); // bind our VAO glDrawElements(GL_TRIANGLES, scene->mMeshes[i]->mNumFaces*3, GL_UNSIGNED_INT, 0); glBindVertexArray(0); // unbind our VAO delete [] normalArray; delete [] colorArrayA; delete [] colorArrayD; delete [] colorArrayS; } shader->unbind(); app->display(); return; } void assimpRenderer::handleEvents() { sf::Event event; while (app->pollEvent(event)) { if (event.type == sf::Event::Closed) { app->close(); } if ((event.type == sf::Event::KeyPressed) && (event.key.code == sf::Keyboard::Escape)) { app->close(); } if (event.type == sf::Event::Resized) { glViewport(0, 0, event.size.width, event.size.height); } } return; } void assimpRenderer::mainLoop(float modelScale) { while (app->isOpen()) { renderScene(modelScale); handleEvents(); } } bool assimpRenderer::assImport(const std::string& pFile) { // read the file with some example postprocessing scene = importer.ReadFile(pFile, aiProcess_CalcTangentSpace | aiProcess_Triangulate | aiProcess_JoinIdenticalVertices | aiProcess_SortByPType); // if the import failed, report it if (!scene) { std::cerr << "Error: " << importer.GetErrorString() << std::endl; return false; } return true; } void assimpRenderer::genVAOs() { int vboIndex = 0; for (unsigned int i = 0; i < scene->mNumMeshes; i++, vboIndex+=2) { mesh = scene->mMeshes[i]; indexArray = new unsigned int[mesh->mNumFaces * sizeof(unsigned int) * 3]; // convert assimp faces format to array faceIndex = 0; for (unsigned int t = 0; t < mesh->mNumFaces; ++t) { const struct aiFace* face = &mesh->mFaces[t]; std::memcpy(&indexArray[faceIndex], face->mIndices, sizeof(float) * 3); faceIndex += 3; } // generate VAO glGenVertexArrays(1, &vaoID[i]); glBindVertexArray(vaoID[i]); // generate IBO for faces glGenBuffers(1, &iboID[i]); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, iboID[i]); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLuint) * mesh->mNumFaces * 3, indexArray, GL_STATIC_DRAW); // generate VBO for vertices if (mesh->HasPositions()) { glGenBuffers(1, &vboID[vboIndex]); glBindBuffer(GL_ARRAY_BUFFER, vboID[vboIndex]); glBufferData(GL_ARRAY_BUFFER, mesh->mNumVertices * sizeof(GLfloat) * 3, mesh->mVertices, GL_STATIC_DRAW); glEnableVertexAttribArray((GLuint)0); glVertexAttribPointer((GLuint)0, 3, GL_FLOAT, GL_FALSE, 0, 0); } // generate VBO for normals if (mesh->HasNormals()) { normalArray = new float[scene->mMeshes[i]->mNumVertices * 3]; unsigned int normalIndex = 0; for (unsigned int j = 0; j < scene->mMeshes[i]->mNumVertices * 3; j+=3, normalIndex++) { normalArray[j] = scene->mMeshes[i]->mNormals[normalIndex].x; // x normalArray[j+1] = scene->mMeshes[i]->mNormals[normalIndex].y; // y normalArray[j+2] = scene->mMeshes[i]->mNormals[normalIndex].z; // z } normalIndex = 0; glGenBuffers(1, &vboID[vboIndex+1]); glBindBuffer(GL_ARRAY_BUFFER, vboID[vboIndex+1]); glBufferData(GL_ARRAY_BUFFER, mesh->mNumVertices * sizeof(GLfloat) * 3, normalArray, GL_STATIC_DRAW); glEnableVertexAttribArray((GLuint)1); glVertexAttribPointer((GLuint)1, 3, GL_FLOAT, GL_FALSE, 0, 0); delete [] normalArray; } // tex coord stuff goes here // unbind buffers glBindVertexArray(0); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0); delete [] indexArray; } vboIndex = 0; return; } } file: shader.vert #version 150 core in vec3 in_Position; in vec3 in_Normal; uniform mat4 projectionMatrix; uniform mat4 viewMatrix; uniform mat4 modelMatrix; uniform vec3 lightPosition; uniform mat3 normalMatrix; smooth out vec3 vVaryingNormal; smooth out vec3 vVaryingLightDir; void main() { // derive MVP and MV matrices mat4 modelViewProjectionMatrix = projectionMatrix * viewMatrix * modelMatrix; mat4 modelViewMatrix = viewMatrix * modelMatrix; // get surface normal in eye coordinates vVaryingNormal = normalMatrix * in_Normal; // get vertex position in eye coordinates vec4 vPosition4 = modelViewMatrix * vec4(in_Position, 1.0); vec3 vPosition3 = vPosition4.xyz / vPosition4.w; // get vector to light source vVaryingLightDir = normalize(lightPosition - vPosition3); // Set the position of the current vertex gl_Position = modelViewProjectionMatrix * vec4(in_Position, 1.0); } file: shader.frag #version 150 core out vec4 out_Color; uniform vec3 ambientColor; uniform vec3 diffuseColor; uniform vec3 specularColor; smooth in vec3 vVaryingNormal; smooth in vec3 vVaryingLightDir; void main() { // dot product gives us diffuse intensity float diff = max(0.0, dot(normalize(vVaryingNormal), normalize(vVaryingLightDir))); // multiply intensity by diffuse color, force alpha to 1.0 out_Color = vec4(diff * diffuseColor, 1.0); // add in ambient light out_Color += vec4(ambientColor, 1.0); // specular light vec3 vReflection = normalize(reflect(-normalize(vVaryingLightDir), normalize(vVaryingNormal))); float spec = max(0.0, dot(normalize(vVaryingNormal), vReflection)); if (diff != 0) { float fSpec = pow(spec, 128.0); // Set the output color of our current pixel out_Color.rgb += vec3(fSpec, fSpec, fSpec); } } I know it's a lot to look through, but I'm putting most of the code up so as not to assume where the problem is. Thanks in advance to anyone who has some time to help me pinpoint the problem(s)! I've been trying to sort it out for two days now and I'm not getting anywhere on my own.

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  • How to know whether to create a general system or to hack a solution

    - by Andy K
    I'm new to coding , learning it since last year actually. One of my worst habits is the following: Often I'm trying to create a solution that is too big , too complex and doesn't achieve what needs to be achieved, when a hacky kludge can make the fit. One last example was the following (see paste bin link below) http://pastebin.com/WzR3zsLn After explaining my issue, one nice person at stackoverflow came with this solution instead http://stackoverflow.com/questions/25304170/update-a-field-by-removing-quarter-or-removing-month When should I keep my code simple and when should I create a 'big', general solution? I feel stupid sometimes for building something so big, so awkward, just to solve a simple problem. It did not occur to me that there would be an easier solution. Any tips are welcomed. Best

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  • ASP.NET MVC Paging/Sorting/Filtering a list using ModelMetadata

    - by rajbk
    This post looks at how to control paging, sorting and filtering when displaying a list of data by specifying attributes in your Model using the ASP.NET MVC framework and the excellent MVCContrib library. It also shows how to hide/show columns and control the formatting of data using attributes.  This uses the Northwind database. A sample project is attached at the end of this post. Let’s start by looking at a class called ProductViewModel. The properties in the class are decorated with attributes. The OrderBy attribute tells the system that the Model can be sorted using that property. The SearchFilter attribute tells the system that filtering is allowed on that property. Filtering type is set by the  FilterType enum which currently supports Equals and Contains. The ScaffoldColumn property specifies if a column is hidden or not The DisplayFormat specifies how the data is formatted. public class ProductViewModel { [OrderBy(IsDefault = true)] [ScaffoldColumn(false)] public int? ProductID { get; set; }   [SearchFilter(FilterType.Contains)] [OrderBy] [DisplayName("Product Name")] public string ProductName { get; set; }   [OrderBy] [DisplayName("Unit Price")] [DisplayFormat(DataFormatString = "{0:c}")] public System.Nullable<decimal> UnitPrice { get; set; }   [DisplayName("Category Name")] public string CategoryName { get; set; }   [SearchFilter] [ScaffoldColumn(false)] public int? CategoryID { get; set; }   [SearchFilter] [ScaffoldColumn(false)] public int? SupplierID { get; set; }   [OrderBy] public bool Discontinued { get; set; } } Before we explore the code further, lets look at the UI.  The UI has a section for filtering the data. The column headers with links are sortable. Paging is also supported with the help of a pager row. The pager is rendered using the MVCContrib Pager component. The data is displayed using a customized version of the MVCContrib Grid component. The customization was done in order for the Grid to be aware of the attributes mentioned above. Now, let’s look at what happens when we perform actions on this page. The diagram below shows the process: The form on the page has its method set to “GET” therefore we see all the parameters in the query string. The query string is shown in blue above. This query gets routed to an action called Index with parameters of type ProductViewModel and PageSortOptions. The parameters in the query string get mapped to the input parameters using model binding. The ProductView object created has the information needed to filter data while the PageAndSorting object is used for paging and sorting the data. The last block in the figure above shows how the filtered and paged list is created. We receive a product list from our product repository (which is of type IQueryable) and first filter it by calliing the AsFiltered extension method passing in the productFilters object and then call the AsPagination extension method passing in the pageSort object. The AsFiltered extension method looks at the type of the filter instance passed in. It skips properties in the instance that do not have the SearchFilter attribute. For properties that have the SearchFilter attribute, it adds filter expression trees to filter against the IQueryable data. The AsPagination extension method looks at the type of the IQueryable and ensures that the column being sorted on has the OrderBy attribute. If it does not find one, it looks for the default sort field [OrderBy(IsDefault = true)]. It is required that at least one attribute in your model has the [OrderBy(IsDefault = true)]. This because a person could be performing paging without specifying an order by column. As you may recall the LINQ Skip method now requires that you call an OrderBy method before it. Therefore we need a default order by column to perform paging. The extension method adds a order expressoin tree to the IQueryable and calls the MVCContrib AsPagination extension method to page the data. Implementation Notes Auto Postback The search filter region auto performs a get request anytime the dropdown selection is changed. This is implemented using the following jQuery snippet $(document).ready(function () { $("#productSearch").change(function () { this.submit(); }); }); Strongly Typed View The code used in the Action method is shown below: public ActionResult Index(ProductViewModel productFilters, PageSortOptions pageSortOptions) { var productPagedList = productRepository.GetProductsProjected().AsFiltered(productFilters).AsPagination(pageSortOptions);   var productViewFilterContainer = new ProductViewFilterContainer(); productViewFilterContainer.Fill(productFilters.CategoryID, productFilters.SupplierID, productFilters.ProductName);   var gridSortOptions = new GridSortOptions { Column = pageSortOptions.Column, Direction = pageSortOptions.Direction };   var productListContainer = new ProductListContainerModel { ProductPagedList = productPagedList, ProductViewFilterContainer = productViewFilterContainer, GridSortOptions = gridSortOptions };   return View(productListContainer); } As you see above, the object that is returned to the view is of type ProductListContainerModel. This contains all the information need for the view to render the Search filter section (including dropdowns),  the Html.Pager (MVCContrib) and the Html.Grid (from MVCContrib). It also stores the state of the search filters so that they can recreate themselves when the page reloads (Viewstate, I miss you! :0)  The class diagram for the container class is shown below.   Custom MVCContrib Grid The MVCContrib grid default behavior was overridden so that it would auto generate the columns and format the columns based on the metadata and also make it aware of our custom attributes (see MetaDataGridModel in the sample code). The Grid ensures that the ShowForDisplay on the column is set to true This can also be set by the ScaffoldColumn attribute ref: http://bradwilson.typepad.com/blog/2009/10/aspnet-mvc-2-templates-part-2-modelmetadata.html) Column headers are set using the DisplayName attribute Column sorting is set using the OrderBy attribute. The data is formatted using the DisplayFormat attribute. Generic Extension methods for Sorting and Filtering The extension method AsFiltered takes in an IQueryable<T> and uses expression trees to query against the IQueryable data. The query is constructed using the Model metadata and the properties of the T filter (productFilters in our case). Properties in the Model that do not have the SearchFilter attribute are skipped when creating the filter expression tree.  It returns an IQueryable<T>. The extension method AsPagination takes in an IQuerable<T> and first ensures that the column being sorted on has the OrderBy attribute. If not, we look for the default OrderBy column ([OrderBy(IsDefault = true)]). We then build an expression tree to sort on this column. We finally hand off the call to the MVCContrib AsPagination which returns an IPagination<T>. This type as you can see in the class diagram above is passed to the view and used by the MVCContrib Grid and Pager components. Custom Provider To get the system to recognize our custom attributes, we create our MetadataProvider as mentioned in this article (http://bradwilson.typepad.com/blog/2010/01/why-you-dont-need-modelmetadataattributes.html) protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName) { ModelMetadata metadata = base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName);   SearchFilterAttribute searchFilterAttribute = attributes.OfType<SearchFilterAttribute>().FirstOrDefault(); if (searchFilterAttribute != null) { metadata.AdditionalValues.Add(Globals.SearchFilterAttributeKey, searchFilterAttribute); }   OrderByAttribute orderByAttribute = attributes.OfType<OrderByAttribute>().FirstOrDefault(); if (orderByAttribute != null) { metadata.AdditionalValues.Add(Globals.OrderByAttributeKey, orderByAttribute); }   return metadata; } We register our MetadataProvider in Global.asax.cs. protected void Application_Start() { AreaRegistration.RegisterAllAreas();   RegisterRoutes(RouteTable.Routes);   ModelMetadataProviders.Current = new MvcFlan.QueryModelMetaDataProvider(); } Bugs, Comments and Suggestions are welcome! You can download the sample code below. This code is purely experimental. Use at your own risk. Download Sample Code (VS 2010 RTM) MVCNorthwindSales.zip

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  • Using the West Wind Web Toolkit to set up AJAX and REST Services

    - by Rick Strahl
    I frequently get questions about which option to use for creating AJAX and REST backends for ASP.NET applications. There are many solutions out there to do this actually, but when I have a choice - not surprisingly - I fall back to my own tools in the West Wind West Wind Web Toolkit. I've talked a bunch about the 'in-the-box' solutions in the past so for a change in this post I'll talk about the tools that I use in my own and customer applications to handle AJAX and REST based access to service resources using the West Wind West Wind Web Toolkit. Let me preface this by saying that I like things to be easy. Yes flexible is very important as well but not at the expense of over-complexity. The goal I've had with my tools is make it drop dead easy, with good performance while providing the core features that I'm after, which are: Easy AJAX/JSON Callbacks Ability to return any kind of non JSON content (string, stream, byte[], images) Ability to work with both XML and JSON interchangeably for input/output Access endpoints via POST data, RPC JSON calls, GET QueryString values or Routing interface Easy to use generic JavaScript client to make RPC calls (same syntax, just what you need) Ability to create clean URLS with Routing Ability to use standard ASP.NET HTTP Stack for HTTP semantics It's all about options! In this post I'll demonstrate most of these features (except XML) in a few simple and short samples which you can download. So let's take a look and see how you can build an AJAX callback solution with the West Wind Web Toolkit. Installing the Toolkit Assemblies The easiest and leanest way of using the Toolkit in your Web project is to grab it via NuGet: West Wind Web and AJAX Utilities (Westwind.Web) and drop it into the project by right clicking in your Project and choosing Manage NuGet Packages from anywhere in the Project.   When done you end up with your project looking like this: What just happened? Nuget added two assemblies - Westwind.Web and Westwind.Utilities and the client ww.jquery.js library. It also added a couple of references into web.config: The default namespaces so they can be accessed in pages/views and a ScriptCompressionModule that the toolkit optionally uses to compress script resources served from within the assembly (namely ww.jquery.js and optionally jquery.js). Creating a new Service The West Wind Web Toolkit supports several ways of creating and accessing AJAX services, but for this post I'll stick to the lower level approach that works from any plain HTML page or of course MVC, WebForms, WebPages. There's also a WebForms specific control that makes this even easier but I'll leave that for another post. So, to create a new standalone AJAX/REST service we can create a new HttpHandler in the new project either as a pure class based handler or as a generic .ASHX handler. Both work equally well, but generic handlers don't require any web.config configuration so I'll use that here. In the root of the project add a Generic Handler. I'm going to call this one StockService.ashx. Once the handler has been created, edit the code and remove all of the handler body code. Then change the base class to CallbackHandler and add methods that have a [CallbackMethod] attribute. Here's the modified base handler implementation now looks like with an added HelloWorld method: using System; using Westwind.Web; namespace WestWindWebAjax { /// <summary> /// Handler implements CallbackHandler to provide REST/AJAX services /// </summary> public class SampleService : CallbackHandler { [CallbackMethod] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } } } Notice that the class inherits from CallbackHandler and that the HelloWorld service method is marked up with [CallbackMethod]. We're done here. Services Urlbased Syntax Once you compile, the 'service' is live can respond to requests. All CallbackHandlers support input in GET and POST formats, and can return results as JSON or XML. To check our fancy HelloWorld method we can now access the service like this: http://localhost/WestWindWebAjax/StockService.ashx?Method=HelloWorld&name=Rick which produces a default JSON response - in this case a string (wrapped in quotes as it's JSON): (note by default JSON will be downloaded by most browsers not displayed - various options are available to view JSON right in the browser) If I want to return the same data as XML I can tack on a &format=xml at the end of the querystring which produces: <string>Hello Rick. Time is: 11/1/2011 12:11:13 PM</string> Cleaner URLs with Routing Syntax If you want cleaner URLs for each operation you can also configure custom routes on a per URL basis similar to the way that WCF REST does. To do this you need to add a new RouteHandler to your application's startup code in global.asax.cs one for each CallbackHandler based service you create: protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); } With this code in place you can now add RouteUrl properties to any of your service methods. For the HelloWorld method that doesn't make a ton of sense but here is what a routed clean URL might look like in definition: [CallbackMethod(RouteUrl="stocks/HelloWorld/{name}")] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } The same URL I previously used now becomes a bit shorter and more readable with: http://localhost/WestWindWebAjax/HelloWorld/Rick It's an easy way to create cleaner URLs and still get the same functionality. Calling the Service with $.getJSON() Since the result produced is JSON you can now easily consume this data using jQuery's getJSON method. First we need a couple of scripts - jquery.js and ww.jquery.js in the page: <!DOCTYPE html> <html> <head> <link href="Css/Westwind.css" rel="stylesheet" type="text/css" /> <script src="scripts/jquery.min.js" type="text/javascript"></script> <script src="scripts/ww.jquery.min.js" type="text/javascript"></script> </head> <body> Next let's add a small HelloWorld example form (what else) that has a single textbox to type a name, a button and a div tag to receive the result: <fieldset> <legend>Hello World</legend> Please enter a name: <input type="text" name="txtHello" id="txtHello" value="" /> <input type="button" id="btnSayHello" value="Say Hello (POST)" /> <input type="button" id="btnSayHelloGet" value="Say Hello (GET)" /> <div id="divHelloMessage" class="errordisplay" style="display:none;width: 450px;" > </div> </fieldset> Then to call the HelloWorld method a little jQuery is used to hook the document startup and the button click followed by the $.getJSON call to retrieve the data from the server. <script type="text/javascript"> $(document).ready(function () { $("#btnSayHelloGet").click(function () { $.getJSON("SampleService.ashx", { Method: "HelloWorld", name: $("#txtHello").val() }, function (result) { $("#divHelloMessage") .text(result) .fadeIn(1000); }); });</script> .getJSON() expects a full URL to the endpoint of our service, which is the ASHX file. We can either provide a full URL (SampleService.ashx?Method=HelloWorld&name=Rick) or we can just provide the base URL and an object that encodes the query string parameters for us using an object map that has a property that matches each parameter for the server method. We can also use the clean URL routing syntax, but using the object parameter encoding actually is safer as the parameters will get properly encoded by jQuery. The result returned is whatever the result on the server method is - in this case a string. The string is applied to the divHelloMessage element and we're done. Obviously this is a trivial example, but it demonstrates the basics of getting a JSON response back to the browser. AJAX Post Syntax - using ajaxCallMethod() The previous example allows you basic control over the data that you send to the server via querystring parameters. This works OK for simple values like short strings, numbers and boolean values, but doesn't really work if you need to pass something more complex like an object or an array back up to the server. To handle traditional RPC type messaging where the idea is to map server side functions and results to a client side invokation, POST operations can be used. The easiest way to use this functionality is to use ww.jquery.js and the ajaxCallMethod() function. ww.jquery wraps jQuery's AJAX functions and knows implicitly how to call a CallbackServer method with parameters and parse the result. Let's look at another simple example that posts a simple value but returns something more interesting. Let's start with the service method: [CallbackMethod(RouteUrl="stocks/{symbol}")] public StockQuote GetStockQuote(string symbol) { Response.Cache.SetExpires(DateTime.UtcNow.Add(new TimeSpan(0, 2, 0))); StockServer server = new StockServer(); var quote = server.GetStockQuote(symbol); if (quote == null) throw new ApplicationException("Invalid Symbol passed."); return quote; } This sample utilizes a small StockServer helper class (included in the sample) that downloads a stock quote from Yahoo's financial site via plain HTTP GET requests and formats it into a StockQuote object. Lets create a small HTML block that lets us query for the quote and display it: <fieldset> <legend>Single Stock Quote</legend> Please enter a stock symbol: <input type="text" name="txtSymbol" id="txtSymbol" value="msft" /> <input type="button" id="btnStockQuote" value="Get Quote" /> <div id="divStockDisplay" class="errordisplay" style="display:none; width: 450px;"> <div class="label-left">Company:</div> <div id="stockCompany"></div> <div class="label-left">Last Price:</div> <div id="stockLastPrice"></div> <div class="label-left">Quote Time:</div> <div id="stockQuoteTime"></div> </div> </fieldset> The final result looks something like this:   Let's hook up the button handler to fire the request and fill in the data as shown: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").show().fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, HH:mm EST")); }, onPageError); }); So we point at SampleService.ashx and the GetStockQuote method, passing a single parameter of the input symbol value. Then there are two handlers for success and failure callbacks.  The success handler is the interesting part - it receives the stock quote as a result and assigns its values to various 'holes' in the stock display elements. The data that comes back over the wire is JSON and it looks like this: { "Symbol":"MSFT", "Company":"Microsoft Corpora", "OpenPrice":26.11, "LastPrice":26.01, "NetChange":0.02, "LastQuoteTime":"2011-11-03T02:00:00Z", "LastQuoteTimeString":"Nov. 11, 2011 4:20pm" } which is an object representation of the data. JavaScript can evaluate this JSON string back into an object easily and that's the reslut that gets passed to the success function. The quote data is then applied to existing page content by manually selecting items and applying them. There are other ways to do this more elegantly like using templates, but here we're only interested in seeing how the data is returned. The data in the object is typed - LastPrice is a number and QuoteTime is a date. Note about the date value: JavaScript doesn't have a date literal although the JSON embedded ISO string format used above  ("2011-11-03T02:00:00Z") is becoming fairly standard for JSON serializers. However, JSON parsers don't deserialize dates by default and return them by string. This is why the StockQuote actually returns a string value of LastQuoteTimeString for the same date. ajaxMethodCallback always converts dates properly into 'real' dates and the example above uses the real date value along with a .formatDate() data extension (also in ww.jquery.js) to display the raw date properly. Errors and Exceptions So what happens if your code fails? For example if I pass an invalid stock symbol to the GetStockQuote() method you notice that the code does this: if (quote == null) throw new ApplicationException("Invalid Symbol passed."); CallbackHandler automatically pushes the exception message back to the client so it's easy to pick up the error message. Regardless of what kind of error occurs: Server side, client side, protocol errors - any error will fire the failure handler with an error object parameter. The error is returned to the client via a JSON response in the error callback. In the previous examples I called onPageError which is a generic routine in ww.jquery that displays a status message on the bottom of the screen. But of course you can also take over the error handling yourself: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); }, function (error, xhr) { $("#divErrorDisplay").text(error.message).fadeIn(1000); }); }); The error object has a isCallbackError, message and  stackTrace properties, the latter of which is only populated when running in Debug mode, and this object is returned for all errors: Client side, transport and server side errors. Regardless of which type of error you get the same object passed (as well as the XHR instance optionally) which makes for a consistent error retrieval mechanism. Specifying HttpVerbs You can also specify HTTP Verbs that are allowed using the AllowedHttpVerbs option on the CallbackMethod attribute: [CallbackMethod(AllowedHttpVerbs=HttpVerbs.GET | HttpVerbs.POST)] public string HelloWorld(string name) { … } If you're building REST style API's this might be useful to force certain request semantics onto the client calling. For the above if call with a non-allowed HttpVerb the request returns a 405 error response along with a JSON (or XML) error object result. The default behavior is to allow all verbs access (HttpVerbs.All). Passing in object Parameters Up to now the parameters I passed were very simple. But what if you need to send something more complex like an object or an array? Let's look at another example now that passes an object from the client to the server. Keeping with the Stock theme here lets add a method called BuyOrder that lets us buy some shares for a stock. Consider the following service method that receives an StockBuyOrder object as a parameter: [CallbackMethod] public string BuyStock(StockBuyOrder buyOrder) { var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } public class StockBuyOrder { public string Symbol { get; set; } public int Quantity { get; set; } public DateTime BuyOn { get; set; } public StockBuyOrder() { BuyOn = DateTime.Now; } } This is a contrived do-nothing example that simply echoes back what was passed in, but it demonstrates how you can pass complex data to a callback method. On the client side we now have a very simple form that captures the three values on a form: <fieldset> <legend>Post a Stock Buy Order</legend> Enter a symbol: <input type="text" name="txtBuySymbol" id="txtBuySymbol" value="GLD" />&nbsp;&nbsp; Qty: <input type="text" name="txtBuyQty" id="txtBuyQty" value="10" style="width: 50px" />&nbsp;&nbsp; Buy on: <input type="text" name="txtBuyOn" id="txtBuyOn" value="<%= DateTime.Now.ToString("d") %>" style="width: 70px;" /> <input type="button" id="btnBuyStock" value="Buy Stock" /> <div id="divStockBuyMessage" class="errordisplay" style="display:none"></div> </fieldset> The completed form and demo then looks something like this:   The client side code that picks up the input values and assigns them to object properties and sends the AJAX request looks like this: $("#btnBuyStock").click(function () { // create an object map that matches StockBuyOrder signature var buyOrder = { Symbol: $("#txtBuySymbol").val(), Quantity: $("#txtBuyQty").val() * 1, // number Entered: new Date() } ajaxCallMethod("SampleService.ashx", "BuyStock", [buyOrder], function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError); }); The code creates an object and attaches the properties that match the server side object passed to the BuyStock method. Each property that you want to update needs to be included and the type must match (ie. string, number, date in this case). Any missing properties will not be set but also not cause any errors. Pass POST data instead of Objects In the last example I collected a bunch of values from form variables and stuffed them into object variables in JavaScript code. While that works, often times this isn't really helping - I end up converting my types on the client and then doing another conversion on the server. If lots of input controls are on a page and you just want to pick up the values on the server via plain POST variables - that can be done too - and it makes sense especially if you're creating and filling the client side object only to push data to the server. Let's add another method to the server that once again lets us buy a stock. But this time let's not accept a parameter but rather send POST data to the server. Here's the server method receiving POST data: [CallbackMethod] public string BuyStockPost() { StockBuyOrder buyOrder = new StockBuyOrder(); buyOrder.Symbol = Request.Form["txtBuySymbol"]; ; int qty; int.TryParse(Request.Form["txtBuyQuantity"], out qty); buyOrder.Quantity = qty; DateTime time; DateTime.TryParse(Request.Form["txtBuyBuyOn"], out time); buyOrder.BuyOn = time; // Or easier way yet //FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } Clearly we've made this server method take more code than it did with the object parameter. We've basically moved the parameter assignment logic from the client to the server. As a result the client code to call this method is now a bit shorter since there's no client side shuffling of values from the controls to an object. $("#btnBuyStockPost").click(function () { ajaxCallMethod("SampleService.ashx", "BuyStockPost", [], // Note: No parameters - function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError, // Force all page Form Variables to be posted { postbackMode: "Post" }); }); The client simply calls the BuyStockQuote method and pushes all the form variables from the page up to the server which parses them instead. The feature that makes this work is one of the options you can pass to the ajaxCallMethod() function: { postbackMode: "Post" }); which directs the function to include form variable POST data when making the service call. Other options include PostNoViewState (for WebForms to strip out WebForms crap vars), PostParametersOnly (default), None. If you pass parameters those are always posted to the server except when None is set. The above code can be simplified a bit by using the FormVariableBinder helper, which can unbind form variables directly into an object: FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); which replaces the manual Request.Form[] reading code. It receives the object to unbind into, a string of properties to skip, and an optional prefix which is stripped off form variables to match property names. The component is similar to the MVC model binder but it's independent of MVC. Returning non-JSON Data CallbackHandler also supports returning non-JSON/XML data via special return types. You can return raw non-JSON encoded strings like this: [CallbackMethod(ReturnAsRawString=true,ContentType="text/plain")] public string HelloWorldNoJSON(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } Calling this method results in just a plain string - no JSON encoding with quotes around the result. This can be useful if your server handling code needs to return a string or HTML result that doesn't fit well for a page or other UI component. Any string output can be returned. You can also return binary data. Stream, byte[] and Bitmap/Image results are automatically streamed back to the client. Notice that you should set the ContentType of the request either on the CallbackMethod attribute or using Response.ContentType. This ensures the Web Server knows how to display your binary response. Using a stream response makes it possible to return any of data. Streamed data can be pretty handy to return bitmap data from a method. The following is a method that returns a stock history graph for a particular stock over a provided number of years: [CallbackMethod(ContentType="image/png",RouteUrl="stocks/history/graph/{symbol}/{years}")] public Stream GetStockHistoryGraph(string symbol, int years = 2,int width = 500, int height=350) { if (width == 0) width = 500; if (height == 0) height = 350; StockServer server = new StockServer(); return server.GetStockHistoryGraph(symbol,"Stock History for " + symbol,width,height,years); } I can now hook this up into the JavaScript code when I get a stock quote. At the end of the process I can assign the URL to the service that returns the image into the src property and so force the image to display. Here's the changed code: $("#btnStockQuote").click(function () { var symbol = $("#txtSymbol").val(); ajaxCallMethod("SampleService.ashx", "GetStockQuote", [symbol], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); // display a stock chart $("#imgStockHistory").attr("src", "stocks/history/graph/" + symbol + "/2"); },onPageError); }); The resulting output then looks like this: The charting code uses the new ASP.NET 4.0 Chart components via code to display a bar chart of the 2 year stock data as part of the StockServer class which you can find in the sample download. The ability to return arbitrary data from a service is useful as you can see - in this case the chart is clearly associated with the service and it's nice that the graph generation can happen off a handler rather than through a page. Images are common resources, but output can also be PDF reports, zip files for downloads etc. which is becoming increasingly more common to be returned from REST endpoints and other applications. Why reinvent? Obviously the examples I've shown here are pretty basic in terms of functionality. But I hope they demonstrate the core features of AJAX callbacks that you need to work through in most applications which is simple: return data, send back data and potentially retrieve data in various formats. While there are other solutions when it comes down to making AJAX callbacks and servicing REST like requests, I like the flexibility my home grown solution provides. Simply put it's still the easiest solution that I've found that addresses my common use cases: AJAX JSON RPC style callbacks Url based access XML and JSON Output from single method endpoint XML and JSON POST support, querystring input, routing parameter mapping UrlEncoded POST data support on callbacks Ability to return stream/raw string data Essentially ability to return ANYTHING from Service and pass anything All these features are available in various solutions but not together in one place. I've been using this code base for over 4 years now in a number of projects both for myself and commercial work and it's served me extremely well. Besides the AJAX functionality CallbackHandler provides, it's also an easy way to create any kind of output endpoint I need to create. Need to create a few simple routines that spit back some data, but don't want to create a Page or View or full blown handler for it? Create a CallbackHandler and add a method or multiple methods and you have your generic endpoints.  It's a quick and easy way to add small code pieces that are pretty efficient as they're running through a pretty small handler implementation. I can have this up and running in a couple of minutes literally without any setup and returning just about any kind of data. Resources Download the Sample NuGet: Westwind Web and AJAX Utilities (Westwind.Web) ajaxCallMethod() Documentation Using the AjaxMethodCallback WebForms Control West Wind Web Toolkit Home Page West Wind Web Toolkit Source Code © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  jQuery  AJAX   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Package and Publish Web Sites with TFS 2010 Build Server

    - by jdanforth
    To package and publish web sites with TFS 2010 Build Server, you can use MSDeploy and some of the new MSBuild arguments. For example: /p:DeployOnBuild=True /p:DeployTarget=MsDeployPublish /p:MSDeployPublishMethod=InProc /p:CreatePackageOnPublish=True /p:DeployIisAppPath="Default Web Site/WebApplication1" /p:MsDeployServiceUrl=localhost Does all the work for you! Unfortunately these arguments are not very well documented, yet. Please feel free comment with pointers to good docs. You can enter these arguments when editing the Build Definition, under the Process tab and the Advanced section: If you’re working with these things, I’m sure you’ve not missed the PDC 2009 presentation by Vishal Joshi about MS Deploy. A few links on the topic: http://stackoverflow.com/questions/2636153/where-is-the-documentation-for-msbuild-arguments-to-run-msdeploy http://blogs.msdn.com/aspnetue/archive/2010/03/05/automated-deployment-in-asp-net-4-frequently-asked-questions.aspx http://www.hanselman.com/blog/WebDeploymentMadeAwesomeIfYoureUsingXCopyYoureDoingItWrong.aspx

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  • Ask How-To Geek: Learning the Office Ribbon, Booting to USB with an Old BIOS, and Snapping Windows

    - by Jason Fitzpatrick
    You’ve got questions and we’ve got answers. Today we highlight how to master the new Office interface, USB boot a computer with outdated BIOS, and snap windows to preset locations. Learning the New Office Ribbon Dear How-To Geek, I feel silly asking this (in light of how long the new Office interface has been out) but my company finally got around to upgrading from Windows XP and Office 2000 so the new interface it totally new to me. Can you recommend any resources for quickly learning the Office ribbon and the new changes? I feel completely lost after two decades of the old Office interface. Help! Sincerely, Where the Hell is Everything? Dear Where the Hell, We think most people were with you at some point in the last few years. “Where the hell is…” could possibly be the slogan for the new ribbon interface. You could browse through some of the dry tutorials online or even get a weighty book on the topic but the best way to learn something new is to get hands on. Ribbon Hero turns learning the new Office features and ribbon layout into a game. It’s no vigorous round of Team Fortress mind you, but it’s significantly more fun than reading a training document. Check out how to install and configure Ribbon Hero here. You’ll be teaching your coworkers new tricks in no time. Boot via USB with an Old BIOS Dear How-To Geek, I’m trying to repurpose some old computers by updating them with lightweight Linux distros but the BIOS on most of the machines is ancient and creaky. How ancient? It doesn’t even support booting from a USB device! I have a large flash drive that I’ve turned into a master installation tool for jobs like this but I can’t use it. The computers in question have USB ports; they just aren’t recognized during the boot process. What can I do? USB Bootin’ in Boise Dear USB Bootin’, It’s great you’re working to breathe life into old hardware! You’ve run into one of the limitations of older BIOSes, USB was around but nobody was thinking about booting off of it. Fortunately if you have a computer old enough to have that kind of BIOS it’s likely to also has a floppy drive or a CDROM drive. While you could make a bootable CDROM for your application we understand that you want to keep using the master USB installer you’ve made. In light of that we recommend PLoP Boot Manager. Think of it like a boot manager for your boot manager. Using it you can create a bootable floppy or CDROM that will enable USB booting of your master USB drive. Make a CD and a floppy version and you’ll have everything in your toolkit you need for future computer refurbishing projects. Read up on creating bootable media with PLoP Boot Manager here. Snapping Windows to Preset Coordinates Dear How-To Geek, Once upon a time I had a company laptop that came with a little utility that snapped windows to preset areas of the screen. This was long before the snap-to-side features in Windows 7. You could essentially configure your screen into a grid pattern of your choosing and then windows would neatly snap into those grids. I have no idea what it was called or if was anymore than a gimmick from the computer manufacturer, but I’d really like to have it on my new computer! Bend and Snap in San Francisco, Dear Bend and Snap, If we had to guess, we’d guess your company must have had a set of laptops from Acer as the program you’re describing sounds exactly like Acer GridVista. Fortunately for you the application was extremely popular and Acer released it independently of their hardware. If, by chance, you’ve since upgraded to a multiple monitor setup the app even supports multiple monitors—many of the configurations are handy for arranging IM windows and other auxiliary communication tools. Check out our guide to installing and configuring Acer GridVista here for more information. Have a question you want to put before the How-To Geek staff? Shoot us an email at [email protected] and then keep an eye out for a solution in the Ask How-To Geek column. Latest Features How-To Geek ETC How to Upgrade Windows 7 Easily (And Understand Whether You Should) The How-To Geek Guide to Audio Editing: Basic Noise Removal Install a Wii Game Loader for Easy Backups and Fast Load Times The Best of CES (Consumer Electronics Show) in 2011 The Worst of CES (Consumer Electronics Show) in 2011 HTG Projects: How to Create Your Own Custom Papercraft Toy Download the New Year in Japan Windows 7 Theme from Microsoft Once More Unto the Breach – Facebook Apps Can Now Access Your Address and Phone Number Dial Zero Speeds You Through Annoying Customer Service Menus Complete Dropquest 2011 and Receive Free Dropbox Storage Desktop Computer versus Laptop Wallpaper The Kids Have No Idea What Old Tech Is [Video]

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  • Developer’s Life – Summary of Superhero Articles

    - by Pinal Dave
    Earlier this year, I wrote an article series where I talked about developer’s life and compared it with Superhero. I have got amazing response to this series and I have been receiving quite a lots of email suggesting that I should write more blog post about them. Currently I am not planning to write more blog post but I will soon continue another series. In this blog post, I have summarized the entire series. Let me know if you want me to write about any superhero. I will see what I can do about that hero. Developer’s Life – Every Developer is a Captain America Captain America was first created as a comic book character in the 1940’s as a way to boost morale during World War II.  Aimed at a children’s audience, his legacy faded away when the war ended.  However, he has recently has a major reboot to become a popular movie character that deals with modern issues. Developer’s Life – Every Developer is the Incredible Hulk The Incredible Hulk is possibly one of the scariest superheroes out there.  All superheroes are meant to be “out of this world” and awe-inspiring, but I think most people will agree with I say The Hulk takes this to the next level.  He is the result of an industrial accident, which is scary enough in it’s own right.  Plus, when mild-mannered Bruce Banner is angered, he goes completely out-of-control and transforms into a destructive monster that he cannot control and has no memories of. Developer’s Life – Every Developer is a Wonder Woman We have focused a lot lately on this “superhero series.”  I love fantasy books and movies, and I feel like there is a lot to be learned from them.  As I am writing this series, though, I have noticed that every super hero I write about is a man.  So today, I would like to talk about the major female super hero – Wonder Woman. Developer’s Life – Every Developer is a Harry Potter Harry Potter might not be a superhero in the traditional sense, but I believe he still has a lot to teach us and show us about life as a developer.  If you have been living under a rock for the last 17 years, you might not know that Harry Potter is the main character in an extremely popular series of books and movies documenting the education and tribulation of a young wizard (and his friends). Developer’s Life – Every Developer is Like Transformers Transformers may not be superheroes – they don’t wear capes, they don’t have amazing powers outside of their size and folding ability, they’re not even human (technically).  Part of their enduring popularity is that while we are enjoying over-the-top movies, we are learning about good leadership and strong personal skills. Developer’s Life – Every Developer is a Iron Man Iron Man is another superhero who is not naturally “super,” but relies on his brain (and money) to turn him into a fighting machine.  While traditional superheroes are still popular, a three-movie franchise and incorporation into the new Avengers series shows that Iron Man is popular enough on his own. Developer’s Life – Every Developer is a Sherlock Holmes I have been thinking a lot about how developers are like super heroes, and I have written two blog posts now comparing them to Spiderman and Superman.  I have a lot of love and respect for developers, and I hope that they are enjoying these articles, and others are learning a little bit about the profession.  There is another fictional character who, while not technically asuper hero, is very powerful, and I also think stands as a good example of a developer. That character is Sherlock Holmes.  Sherlock Holmes is a British detective, first made popular at the turn of the 19thcentury by author Sir Arthur Conan Doyle.  The original Sherlock Holmes was a brilliant detective who could solve the most mind-boggling crime through simple observations and deduction. Developer’s Life – Every Developer is a Chhota Bheem Chhota Bheem is a cartoon character that is extremely popular where I live.  He is my daughter’s favorite characters.  I like to say that children love Chhota Bheem more than their parents – it is lucky for us he is not real!  Children love Chhota Bheem because he is the absolute “good guy.”  He is smart, loyal, and strong.  He and his friends live in Dholakpur and fight off their many enemies – and always win – in every episode.  In each episode, they learn something about friendship, bravery, and being kind to others.  Chhota Bheem is a good role model for children, and I think that he is a good role model for developers are well. Developer’s Life – Every Developer is a Batman Batman is one of the darkest superheroes in the fantasy canon.  He does not come to his powers through any sort of magical coincidence or radioactive insect, but through a lot of psychological scarring caused by witnessing the death of his parents.  Despite his dark back story, he possesses a lot of admirable abilities that I feel bear comparison to developers. Developer’s Life – Every Developer is a Superman I enjoyed comparing developers to Spiderman so much, that I have decided to continue the trend and encourage some of my favorite people (developers) with another favorite superhero – Superman.  Superman is probably the most famous superhero – and one of the most inspiring. Developer’s Life – Every Developer is a Spiderman I have to admit, Spiderman is my favorite superhero.  The most recent movie recently was released in theaters, so it has been at the front of my mind for some time. Spiderman was my favorite superhero even before the latest movie came out, but of course I took my whole family to see the movie as soon as I could!  Every one of us loved it, including my daughter.  We all left the movie thinking how great it would be to be Spiderman.  So, with that in mind, I started thinking about how we are like Spiderman in our everyday lives, especially developers. I would like to know which Superhero is your favorite hero! Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: Developer, Superhero

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  • Ruby Drag-n-Drop IDE and Ruby programming related

    - by RPK
    I am writing a small desktop GUI application using Ruby and Gtk2. I am using RubyMine 3 on Linux (Fedora). I created a simple class to create a Gtk Window but now I feel it takes more time to just keep adding code for a Button, Drop Down and TextBox etc. I need to write even more code if the DropDown needs to be populated at run-time. Is there any Ruby Gtk IDE which supports adding Controls with simple drag-n-drop? At least I can focus on the business logic instead of just defining position and sizes of controls. One more question. I subscribed to Ruby-Forum mailing list but it is often flooded with Spam. Which is the official Ruby forum? Recently NetBeans has withdrawn support for Ruby. Is it worth to learn Ruby seriously and use it in commercial environment or not?

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  • The Challenge with HTML5 – In Pictures

    - by dwahlin
    I love working with Web technologies and am looking forward to the new functionality that HTML5 will ultimately bring to the table (some of which can be used today). Having been through the div versus layer battle back in the IE4 and Netscape 4 days I think we’re headed down that road again as a result of browsers implementing features differently. I’ve been spending a lot of time researching and playing around with HTML5 samples and features (mainly because we’re already seeing demand for training on HTML5) and there’s a lot of great stuff there that will truly revolutionize web applications as we know them. However, browsers just aren’t there yet and many people outside of the development world don’t really feel a need to upgrade their browser if it’s working reasonably well (Mom and Dad come to mind) so it’s going to be awhile. There’s a nice test site at http://www.HTML5Test.com that runs through different HTML5 features and scores how well they’re supported. They don’t test for everything and are very clear about that on the site: “The HTML5 test score is only an indication of how well your browser supports the upcoming HTML5 standard and related specifications. It does not try to test all of the new features offered by HTML5, nor does it try to test the functionality of each feature it does detect. Despite these shortcomings we hope that by quantifying the level of support users and web developers will get an idea of how hard the browser manufacturers work on improving their browsers and the web as a development platform. The score is calculated by testing for the many new features of HTML5. Each feature is worth one or more points. Apart from the main HTML5 specification and other specifications created the W3C HTML Working Group, this test also awards points for supporting related drafts and specifications. Some of these specifications were initially part of HTML5, but are now further developed by other W3C working groups. WebGL is also part of this test despite not being developed by the W3C, because it extends the HTML5 canvas element with a 3d context. The test also awards bonus points for supporting audio and video codecs and supporting SVG or MathML embedding in a plain HTML document. These test do not count towards the total score because HTML5 does not specify any required audio or video codec. Also SVG and MathML are not required by HTML5, the specification only specifies rules for how such content should be embedded inside a plain HTML file. Please be aware that the specifications that are being tested are still in development and could change before receiving an official status. In the future new tests will be added for the pieces of the specification that are currently still missing. The maximum number of points that can be scored is 300 at this moment, but this is a moving goalpost.” It looks like their tests haven’t been updated since June, but the numbers are pretty scary as a developer because it means I’m going to have to do a lot of browser sniffing before assuming a particular feature is available to use. Not that much different from what we do today as far as browser sniffing you say? I’d have to disagree since HTML5 takes it to a whole new level. In today’s world we have script libraries such as jQuery (my personal favorite), Prototype, script.aculo.us, YUI Library, MooTools, etc. that handle the heavy lifting for us. Until those libraries handle all of the key HTML5 features available it’s going to be a challenge. Certain features such as Canvas are supported fairly well across most of the major browsers while other features such as audio and video are hit or miss depending upon what codec you want to use. Run the tests yourself to see what passes and what fails for different browsers. You can also view the HTML5 Test Suite Conformance Results at http://test.w3.org/html/tests/reporting/report.htm (a work in progress). The table below lists the scores that the HTML5Test site returned for different browsers I have installed on my desktop PC and laptop. A specific list of tests run and features supported are given when you go to the site. Note that I went ahead and tested the IE9 beta and it didn’t do nearly as good as I expected it would, but it’s not officially out yet so I expect that number will change a lot. Am I opposed to HTML5 as a result of these tests? Of course not - I’m actually really excited about what it offers.  However, I’m trying to be realistic and feel it'll definitely add a new level of headache to the Web application development process having been through something like this many years ago. On the flipside, developers that are able to target a specific browser (typically Intranet apps) or master the cross-browser issues are going to release some pretty sweet applications. Check out http://html5gallery.com/ for a look at some of the more cutting-edge sites out there that use HTML5. Also check out the http://www.beautyoftheweb.com site that Microsoft put together to showcase IE9. Chrome 8 Safari 5 for Windows     Opera 10 Firefox 3.6     Internet Explorer 9 Beta (Note that it’s still beta) Internet Explorer 8

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  • Unity AddExplosionForce not doing anything

    - by Zero
    Recently I've started learning Unity3D. I'm working on a game as an exercise in which you control a space ship and have to dodge asteroids. If you feel like it's getting a bit too much you can hit the space bar, emitting a blast in all directions that repulses nearby asteroids. To create this blast I have the following code: public class PlayerBlastScript : MonoBehaviour { public ParticleSystem BlastEffect; // Update is called once per frame void Update () { if (Input.GetKeyUp(KeyCode.Space)) { Fire(); } } public void Fire() { ParticleEmitter effect = (ParticleEmitter) Instantiate (BlastEffect, transform.position, Quaternion.identity); effect.Emit(); Vector3 explosionPos = transform.position; Collider[] colliders = Physics.OverlapSphere(explosionPos, 25.0f); foreach(Collider hit in colliders) { if (!hit) { continue; } if (hit.rigidbody) { hit.rigidbody.AddExplosionForce(5000.0f, explosionPos, 100.0f); } } } } Even though the blast effect appears, the asteroids are not affected at all. The asteroids are all rigid bodies so what's the problem?

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  • Developer Training – A Conclusive Summary- Part 5

    - by pinaldave
    Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 We have now reached the end of our series about developer training.  I hope you have come away thinking that training is the best way to advance in your company and that you are looking for training opportunities right now.  If you’re still not convinced here are a few things to keep in mind:  Training benefits the employer and the employee. A well trained employee is a happy employee, and a happy employee is more efficient and productive. Training an employee might be expensive, but it is less expensive than hiring a new person. Whether you are looking at him from the employee’s or the company’s point of view, there are always advantages to training. A Broader View This series is definitely written for Developer Training but it is not limited to developers only. There are IT Pro, System Admins, DBAs as well many other technology professionals; this article series is for all professionals in the world. The concepts and take away will remain common across all the platform and regardless of technology affiliation. Pass the Knowledge If I have to pick one advise which is extremely important related to training, I will pick – pass the knowledge. Once you have decided in favor of training, there is more to it than simply showing up and staying awake.  It is always a good idea to take notes – at the very least it will help you stay awake, but they will often serve as a good way to remember your training when you go back to work.  You can also use them to pass your new knowledge on to fellow employees, which can be very fun and rewarding. Right Place, Right Time and Right Training There are so many ways to get developer training.  In-person and on the job training is easy to come by and is the most usual type of training, but don’t overlook my favorite type of training: On Demand.  Being able to learn at your own pace, own place and on your own time will make training a realistic goal for almost every employee. I can think of nothing more important in life than furthering your education.  Especially when you work in a field that is constantly changing – like technology.  Whether you like it or not, training is incredibly important.  That is why I feel it is so important to receive training.  And because there are so many different training formats – live, online, through books, through people – I am certain that we all can find a way to be trained that best suits our goals and personalities. The Teacher Within If you think of anyone who is a master of the technology field or an incredibly successful developer (the obvious examples that spring to mind are Steve Jobs or Bill Gates), you will also find a teacher.  Both these individuals spent their lives developing better technology, but also educating other developers and the public about how to use these technologies and how it can change your life for the better.  I think that we all should strive to be like these wonderful teachers.  We might not be able to change the world, but we can certainly change a few lives around us. Even if we never turn into trainers ourselves , being trained as a student can be a good exercise.  We learn a lot and become better employees – and it would not be a stretch to say that this makes us better individuals, as well. Final Say I think learning and growing in your chosen field is not only a good idea, career-wise, but can be fun, too!  I for one never feel more alive than when I am learning about something I am really passionate about.  I think my job title – technology evangelist – explains how enthusiastic I am about this subject.  But please don’t think that I am thinking of this as someone who wants to train and educate others (although this is also one of my passions).  I am also a passionate student.  I enjoy learning new things and am always on the lookout for new ways to learn and new people to learn from. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Design by Contract with Microsoft .Net Code Contract

    - by Fredrik N
    I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract   Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null.   Pre- and Postconditions   When working with DbC we are specifying pre- and postconditions.  Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT.   There are two kinds of Queries, the Basic Queries  (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration.   Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count].   1. Separate Commands and Queries   When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack.   2. Separate basic queries from derived queries There are two different kinds of queries,  the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query.   3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries.   When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   4. For each command, write a postcondition that specifies the value of every basic query.   For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called)  plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle.   5. For every query and command, decide on a suitable precondition.   We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   6. Write invariants to define unchanging properties of objects.   The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract:   public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

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  • How do you share your craft with non programmers?

    - by EpsilonVector
    Sometimes I feel like a musician who can't play live shows. Programming is a pretty cool skill, and a very broad world, but a lot of it happens "off camera"- in your head, in your office, away from spectators. You can of course talk about programming with other programmers, and there is peer programming, and you do get to create something that you can show to people, but when it comes to explaining to non programmers what is it that you do, or how was your day at work, it's sort of tricky. How do you get the non programmers in your life to understand what is it that you do? NOTE: this is not a repeat of Getting non-programmers to understand the development process, because that question was about managing client expectations.

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  • SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Complete Downloadable List – Day 0 of 31

    - by pinaldave
    This blog post is running list of the blog posts in the series of Interview Questions and Answers. At the end of the 31st day of the month, a FREE PDF will be posted here which can be downloadable for offline review. Please scroll below to see latest post for the day. SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Introduction – Day 1 of 31 In this very first blog post – various aspect of the interview questions and answers are discussed. Some people like the subject for their helpful hints and thought provoking subject, and others dislike these posts because they feel it is nothing more than cheating.  I’d like to discuss the pros and cons of a Question and Answer format here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • EAIESB is happy to announce “Advanced Oracle Healthcare in 21 Days” book

    - by JuergenKress
    This books is written on Latest PS6 (11.1.1.7) and available at the EAIESB website. Looking for additional SOA books or if you have published a book, please feel free to add it to our publications wiki! SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: healthcare,SOA,EAIESB,books,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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