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  • Excel CSV into Nested Dictionary; List Comprehensions

    - by victorhooi
    heya, I have a Excel CSV files with employee records in them. Something like this: mail,first_name,surname,employee_id,manager_id,telephone_number [email protected],john,smith,503422,503423,+65(2)3423-2433 [email protected],george,brown,503097,503098,+65(2)3423-9782 .... I'm using DictReader to put this into a nested dictionary: import csv gd_extract = csv.DictReader(open('filename 20100331 original.csv'), dialect='excel') employees = dict([(row['employee_id'], row) for row in gp_extract]) Is the above the proper way to do it - it does work, but is it the Right Way? Something more efficient? Also, the funny thing is, in IDLE, if I try to print out "employees" at the shell, it seems to cause IDLE to crash (there's approximately 1051 rows). 2. Remove employee_id from inner dict The second issue issue, I'm putting it into a dictionary indexed by employee_id, with the value as a nested dictionary of all the values - however, employee_id is also a key:value inside the nested dictionary, which is a bit redundant? Is there any way to exclude it from the inner dictionary? 3. Manipulate data in comprehension Thirdly, we need do some manipulations to the imported data - for example, all the phone numbers are in the wrong format, so we need to do some regex there. Also, we need to convert manager_id to an actual manager's name, and their email address. Most managers are in the same file, while others are in an external_contractors CSV, which is similar but not quite the same format - I can import that to a separate dict though. Are these two items things that can be done within the single list comprehension, or should I use a for loop? Or does multiple comprehensions work? (sample code would be really awesome here). Or is there a smarter way in Python do it? Cheers, Victor

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  • VS2008 - Find and Replace - Searches too many files.

    - by Pam Bullock
    I've used VS2008 a lot and have never had this problem. However, I started a new job and am using a new machine. Ever since I've gotten here the VS Find feature has been acting funny. I first noticed it when I did a replace all for "All Open Files". The project wouldn't build because the values had actually been replaced in other files within the solution that were not open and didn't even open after I pressed replace all. I have found that I can never use replace all on this machine because I never know what it is going to do. Even if I just do a find on "Current Document", once it's done with the document and I should get that message that says "No more matches found" it actually OPENS another random file from my solution where there is a match and keeps on going. It seems to never make any difference what "Look in" option I've chosen. My coworker has an install off the same disk and claims to not be experiencing this. We're in the middle of a stressful, huge project with a close deadline so I know my boss won't let me do a reinstall. Has anyone else ever had this happen? Anyone know a fix?? Thanks, Pam

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  • Why do programmers have to learn for their whole lives and aren't you afraid of that?

    - by serg555
    Programming technologies are evolving so fast that programmers constantly have to learn more and more to catch up whether you want it or not. Often it is not just learning more in the same direction but starting from a scratch. Lets say you were a topnotch programmer in 1999 who quit for 10 years and went to a job interview in 2009 (funny even to imagine) - how much of your knowledge is still needed? And if we take a carpenter, engineer, doctor or even mathematician - they all are still good specialists after 10 years. So why programming is so not stable? Is it because it is just relatively new or because something important is still missing after 50 years and we can't find it to settle in that direction? Do you think after some time situation will change? Learning something new all the time is exciting and all, but it is starting to worry me that as I become older it will be harder and harder. After all "you can't teach an old dog new tricks" and I'm afraid that at the end I just end up behind college students and become one of those "cobol dinosaurs", only it will be probably "java dinosaurs" by that time.

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  • Service Browser for AMF calls (Flex to Java)

    - by Tehsin
    Has anyone used or is aware of a service browser to test AMF calls? I am looking for a tool similar to ZamfBrowser ( http://www.zamfbrowser.org ), but one that works for the Java environment. ZamfBrowser is geared towards AMFPHP. The idea here is to provide a service browser, that allows developers to test Java services using the AMF protocol, without having to go through the Flex UI all the time. There has got to be something out there already for this, but I can't seem to locate anything..... It's kind of funny and strange that a service browser exists for AMFPHP but not for regular AMF calls in a Java environment. I would imagine something exists under Blaze or LCDS? ... Trying to find it in the docs but can't seem to find anything .... The best alternative I can think of at the moment is to use FlexMonkey to record stuff, and then to simulate it using that....which is okay I guess but still sucks because you have to go in and create the Flex UI first, whereas with something like ZamfBrowser, you simply point it at the service calls, it tells the server-side developers if their code works, etc. generates the required as3 classes for you... and makes the integration process much easier in a large team. Any help or insight would be appreciated :) Thanks!

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  • jQuery Validation plugin results in empty AJAX POST

    - by user305412
    Hi, I have tried to solve this issue for at couple of days with no luck. I have a form, where I use the validation plugin, and when I try to submit it, it submits empty vars. Now, if I remove the validation, everything works fine. Here is my implementation: $(document).ready(function(){ $("#myForm").validate({ rules: { field1: { required: true, minlength: 5 }, field2: { required: true, minlength: 10 } }, messages: { field1: "this is required", field2: "this is required", }, errorLabelContainer: $("#validate_msg"), invalidHandler: function(e, validator) { var errors = validator.numberOfInvalids(); if (errors) { $("#validate_div").show(); } }, onkeyup: false, success: false, submitHandler: function(form) { doAjaxPost(form); } }); }); function doAjaxPost(form) { // do some stuff $(form).ajaxSubmit(); return false; } As I wrote this does not work when I have my validation, BUT if I remove that, and just add an onsubmit="doAjaxPost(this.form); return false"; to my HTML form, it works - any clue??? Now here is the funny thing, everything works as it should in Safari, but not in firefox 3.6.2 (Mac OS X)!

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  • PayPal integration woes: PDT hangs on return to site

    - by Tom
    Hi, I'm implementing PayPal IPN & PDT. After some headache & time at the sandbox, IPN is working well and PDT returns the correct $_GET data. The implementation is as follows: Pass user ID in form to PayPal User buys product and triggers IPN which updates database for given user ID PDT returns transaction ID when user returns to site The return page says "please wait" and repeat-Ajax-checks for the transaction status User is redirected to success/failure page Everything works well, EXCEPT that when using the PayPal ready PHP code for PDT to do a return POST, the page hangs. PayPal waits for a response and the user never gets back to my site. I'm not getting a fail status, just nothing. The funny thing is that once the unknown error occurs, my test domain becomes unresponsive for a short period. The code (PHP): https://www.paypal.com/us/cgi-bin/webscr?cmd=p/xcl/rec/pdt-code-outside If I comment out the POST back, it all works fine. I'm able to pin down the problem to once the code enters the while{} loop. Unfortunately, I'm not experienced enough to write a replacement from scratch for the PayPal code, so would really appreciate any ideas on what might be wrong. The POST back goes to ssl://www.sandbox.paypal.com, and I'm using button code and an authorisation token that have all been created via a sandbox test account. Thanks in advance.

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  • Python - Open default mail client using mailto, with multiple recipients

    - by victorhooi
    Hi, I'm attempting to write a Python function to send an email to a list of users, using the default installed mail client. I want to open the email client, and give the user the opportunity to edit the list of users or the email body. I did some searching, and according to here: http://www.sightspecific.com/~mosh/WWW_FAQ/multrec.html It's apparently against the RFC spec to put multiple comma-delimited recipients in a mailto link. However, that's the way everybody else seems to be doing it. What exactly is the modern stance on this? Anyhow, I found the following two sites: http://2ality.blogspot.com/2009/02/generate-emails-with-mailto-urls-and.html http://www.megasolutions.net/python/invoke-users-standard-mail-client-64348.aspx which seem to suggest solutions using urllib.parse (url.parse.quote for me), and webbrowser.open. I tried the sample code from the first link (2ality.blogspot.com), and that worked fine, and opened my default mail client. However, when I try to use the code in my own module, it seems to open up my default browser, for some weird reason. No funny text in the address bar, it just opens up the browser. The email_incorrect_phone_numbers() function is in the Employees class, which contains a dictionary (employee_dict) of Employee objects, which themselves have a number of employee attributes (sn, givenName, mail etc.). Full code is actually here (http://stackoverflow.com/questions/2963975/python-converting-csv-to-objects-code-design) from urllib.parse import quote import webbrowser .... def email_incorrect_phone_numbers(self): email_list = [] for employee in self.employee_dict.values(): if not PhoneNumberFormats.standard_format.search(employee.telephoneNumber): print(employee.telephoneNumber, employee.sn, employee.givenName, employee.mail) email_list.append(employee.mail) recipients = ', '.join(email_list) webbrowser.open("mailto:%s?subject=%s&body=%s" % (recipients, quote("testing"), quote('testing')) ) Any suggestions? Cheers, Victor

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  • Checking inherited attributes in an 'ancestry' based SQL table

    - by Brendon Muir
    I'm using the ancestry gem to help organise my app's tree structure in the database. It basically writes a childs ancestor information to a special column called 'ancestry'. The ancestry column for a particular child might look like '1/34/87' where the parent of this child is 87, and then 87's parent is 34 and 34's is 1. It seems possible that we could select rows from this table each with a subquery that checks all the ancestors to see if a certain attribute it set. E.g. in my app you can hide an item and its children just by setting the parent element's visibility column to 0. I want to be able to find all the items where none of their ancestors are hidden. I tried converting the slashes to comma's with the REPLACE command but IN required a set of comma separated integers rather than one string with comma separated string numbers. It's funny, because I can do this query in two steps, e.g. retrieve the row, then take its ancestry column, split out the id's and make another query that checks that the id is IN that set of id's and that visibility isn't ever 0 and whala! But joining these into one query seems to be quite a task. Much searching has shown a few answers but none really do what I want. SELECT * FROM t1 WHERE id = 99; 99's ancestry column reads '1/34/87' SELECT * FROM t1 WHERE visibility = 0 AND id IN (1,34,87); kind of backwards, but if this returns no rows then the item is visible. Has anyone come across this before and come up with a solution. I don't really want to go the stored procedure route. It's for a rails app.

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  • How to get the Video-ID of a just uploaded Youtube movie

    - by murze
    Hi, how can i get the video-id of a just uploaded Youtube movie? I'm using this code: $yt = new Zend_Gdata_YouTube($httpClient); // create a new Zend_Gdata_YouTube_VideoEntry object $myVideoEntry = new Zend_Gdata_YouTube_VideoEntry(); // create a new Zend_Gdata_App_MediaFileSource object $filesource = $yt->newMediaFileSource('mytestmovie.mov'); $filesource->setContentType('video/quicktime'); // set slug header $filesource->setSlug('mytestmovie.mov'); // add the filesource to the video entry $myVideoEntry->setMediaSource($filesource); $myVideoEntry->setVideoTitle('My Test Movie'); $myVideoEntry->setVideoDescription('My Test Movie'); $myVideoEntry->setVideoCategory('Comedy'); // Note that category must be a valid YouTube category ! // set keywords, please note that this must be a comma separated string // and that each keyword cannot contain whitespace $myVideoEntry->setVideoTags('cars, funny'); // upload URI for the currently authenticated user $uploadUrl = 'http://uploads.gdata.youtube.com/feeds/api/users/default/uploads'; // try to upload the video, catching a Zend_Gdata_App_HttpException if available // or just a regular Zend_Gdata_App_Exception try { $newEntry = $yt->insertEntry($myVideoEntry, $uploadUrl, 'Zend_Gdata_YouTube_VideoEntry'); } catch (Zend_Gdata_App_HttpException $httpException) { echo $httpException->getRawResponseBody(); } catch (Zend_Gdata_App_Exception $e) { echo $e->getMessage(); } I assume it 'll be a property of $newEntry but i can't seem to find it! Thanks!

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  • PHP Unicode character questions

    - by user271619
    Here's a link I found, which even has a character I need to play with for other projects of mine. http://www.fileformat.info/info/unicode/char/2446/index.htm There is a box with the Title of: "Encodings" on that page. And I am wondering about some of the rows. I obviously need a course on this sort of thing, but I'm wondering what the difference is between "HTML Entity (decimal)" and "HTML Entity (hex)". The funny thing is, which confuses me, I throw those characters on a web page, and they display fine. But I haven't specified any UTF-8 encoding in the php page. <?php $string1 = '&#x2446;'; $string2 = '&#9286;'; echo $string1; echo '<br>'; echo $string2; ?> Does the browser know how to display both automatically? And to make it weirder, I can only see those characters on my Mac, in Firefox. But my windows box doesn't want to show them. I've tested it in chrome, and firefox. Do I need to tell the browsers to view them correctly? Or is it an operating system modification?

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  • item-not-found(404) when trying to get a node using Smackx pubsub

    - by DustMason
    I'm trying to use the latest Smackx trunk to get and then subscribe to a pubsub node. However, openfire just sends me a back an error: item not found (404). I am instantiating the java objects from ColdFusion, so my code snippets might look funny but maybe someone will be able to tell me what I've forgotten. Here's how I create the node: ftype = createObject("java", "org.jivesoftware.smackx.pubsub.FormType"); cform = createObject("java", "org.jivesoftware.smackx.pubsub.ConfigureForm").init(ftype.submit); cform.setPersistentItems(true); cform.setDeliverPayloads(true); caccess = createObject("java", "org.jivesoftware.smackx.pubsub.AccessModel"); cform.setAccessModel(caccess.open); cpublish = createObject("java", "org.jivesoftware.smackx.pubsub.PublishModel"); cform.setPublishModel(cpublish.open); cform.setMaxItems(99); manager = createObject("java", "org.jivesoftware.smackx.pubsub.PubSubManager").init(XMPPConnection); myNode = manager.createNode("subber", cform); And here's how I am trying to get to it (in a different section of code): manager = createObject("java", "org.jivesoftware.smackx.pubsub.PubSubManager").init(XMPPConnection); myNode = manager.getNode("subber"); Immediately upon creating the node I seem to be able to publish to it like so: payload = createObject("java", "org.jivesoftware.smackx.pubsub.SimplePayload").init("book","pubsub:test:book","<book xmlns='pubsub:test:book'><title>Lord of the Rings</title></book>"); item = createObject("java", "org.jivesoftware.smackx.pubsub.Item").init(payload); myNode.publish(item); However, it is the getNode() call that is causing my code to error. I have verified that the nodes are being created by checking the DB used by my openfire server. I can see them in there, properly attributed as leaf nodes, etc. Any advice? Anyone else out there doing anything with XMPP and ColdFusion? I have had great success sending and receiving messages with CF and Smack just haven't had the pubsub working yet :) Thanks!

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  • How do programming languages bind identifiers to functions

    - by sub
    I'm talking about C and/or C++ here as this are the only languages I know used for interpreters where the following could be a problem: If we have an interpreted language X how can a library written for it add functions to the language which can then be called from within programs written in the language? PHP example: substr( $str, 5, 10 ); How is the function substr added to the "function pool" of PHP so it can be called from within scripts? It is easy for PHP storing all registered function names in an array and searching through it as a function is called in a script. However, as there obviously is no eval in C(++), how can the function then be called? I assume PHP doesn't have 100MB of code like: if( identifier == "substr" ) { return PHP_SUBSTR(...); } else if( ... ) { ... } Ha ha, that would be pretty funny. I hope you have understood my question so far. How do interpreters solve this problem? How can I solve this for my own experimental toy interpreter?

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  • Why compiler go to suspend mode when want to open database?

    - by rima
    Dear friend I try to connect to database with a less line for my connection string... I find out s.th in oracle website but i dont know Why when the compiler arrive to the line of open database do nothing????!it go back to GUI,but it like hanging...please help me to solve it. p.s.Its funny the program didnt get me any exception also! these service is active in my computer: > Oracle ORCL VSS Writer Service Start > OracleDBConsolrorcl > OracleJobSchedulerORCL Start > OracleOraDB11g+home1TNSListener Start > oracleServiceORCL Start try { /** * ORCL = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = rima-PC)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl) ) )*/ string oradb = "Data Source=(DESCRIPTION=" + "(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=rima-PC)(PORT=1521)))" + "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcl)));" + "User Id=bird_artus;Password=123456;"; //string oradb = "Data Source=OraDb;User Id=scott;Password=tiger;"; string oradb1 = "Data Source=ORCL;User Id=scott;Password=tiger;"; // C# OracleConnection con = new OracleConnection(); con.ConnectionString = oradb1; String command = "select dname from dept where deptno = 10"; MessageBox.Show(command); OracleDataAdapter oda = new OracleDataAdapter(); oda.SelectCommand = new OracleCommand(); oda.SelectCommand.Connection = con; oda.SelectCommand.CommandText = command; con.Open(); oda.SelectCommand.ExecuteNonQuery(); DataSet ds = new DataSet(); oda.Fill(ds); Console.WriteLine(ds.GetXml()); dataGridView1.DataSource = ds; con.Close(); } catch (Exception ex) { MessageBox.Show(ex.Message.ToString()+Environment.NewLine+ ex.StackTrace.ToString()); }

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  • django - variable declared in base project does not appear in app

    - by unsorted
    I have a variable called STATIC_URL, declared in settings.py in my base project: STATIC_URL = '/site_media/static/' This is used, for example, in my site_base.html, which links to CSS files as follows: <link rel="stylesheet" href="{{ STATIC_URL }}css/site_tabs.css" /> I have a bunch of templates related to different apps which extend site_base.html, and when I look at them in my browser the CSS is linked correctly as <link rel="stylesheet" href="/site_media/static/css/site_tabs.css" /> (These came with a default pinax distribution.) I created a new app called 'courses' which lives in the ...../apps/courses folder. I have a view for one of the pages in courses called courseinstance.html which extends site_base.html just like the other ones. However, when this one renders in my browser it comes out as <link rel="stylesheet" href="css/site_tabs.css" /> as if STATIC_URL were equal to "" for this app. Do I have to make some sort of declaration to get my app to take on the same variable values as the project? I don't have a settings.py file for the app. by the way, the app is listed in my list of INSTALLED_APPS and it gets served up fine, just without the link to the CSS file (so the page looks funny). Thanks in advance for your help.

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  • Registry remotley hacked win 7 need help tracking the perp

    - by user577229
    I was writing some .VBS code at thhe office that would allow certain file extensions to be downloaded without a warning dialog on a w7x32 system. The system I was writing this on is in a lab on a segmented subnet. All web access is via a proxy server. The only means of accessing my machine is via the internet or from within the labs MSFT AD domain. While writing and testing my code I found a message of sorts. Upon refresing the registry to verify my code changed a dword, instead the message HELLO was written and visible in regedit where the dword value wass called for. I took a screen shot and proceeded to edit my code. This same weird behavior occurred last time I was writing registry code except on another internal server. I understand that remote registry access exists for windows systems. I will block this immediately once I return to the office. What I want to know is, can I trace who made this connection? How would I do this? I suspect the cause of this is the cause of other "odd" behaviors I'm experiencing at work such as losing control of my input director master control for over an hour and unchanged code that all of a sudden fails for no logical region. These failures occur at funny times, whenver I'm about to give a demonstration of my test code. I know this sounds crazy however knowledge of the registry component makes this believable. Once the registry can be accessed, the entire system is compromised. Any help or sanity checking is appreciated.

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  • Limiting ssh user account only to access his home directory!

    - by EBAGHAKI
    By reading some tutorials online I used these commands: Make a local group: net localgroup CopsshUsers /ADD Deny access to this group at top level: cacls c:\ /c /e /t /d CopsshUsers Open access to the copSSH installation directory: cacls copssh-inst-dir /c /e /t /r CopsshUsers Add Copssh user to the group above: net localgroup CopsshUsers mysshuser /add simply put these commands will try to create a usergroup that has no permission on your computer and it only have access to the copSSH Installation directory. This is not true, since you cannot change the permission on your windows directory, the third command won't remove access to windows folder (it says access denied on his log). Somehow I achieved that by taking ownership of Windows folder and then i execute the third command so CopsshUsers has no permissions on windows folder from now on. Now i tried to SSH to the server and it simply can't login! this is kind of funny because with permission on windows directory you can login and without it you can't!! So if you CAN SSH to the server somehow you know that you have access to the windows directory! (Is this really true??) Simple task: Limiting ssh user account only to access his home directory on WINDOWS and nothing else! Guys please help!

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  • Interesting questions related to lighttpd on Amazon EC2

    - by terence410
    This problem appeared today and I have no idea what is going on. Please share you ideas. I have 1 EC2 DB server (MYSQL + NFS File Sharing + Memcached). And I have 3 EC2 Web servers (lighttpd) where it will mounted the NFS folders on the DB server. Everything going smoothly for months but suddenly there is an interesting phenomenon. In every 8 minutes to 10 minutes, PHP file will be unreachable. This will last about 1 minute and then back to normal. Normal files like .html file are unaffected. All servers have the same problem exactly at the same time. I have spent one whole day to analysis the reason. Finally, I find out when the problem appear, the file descriptor of lighttpd suddenly increased a lot. I used ls /proc/1234/fd | wc -l to check the number of fd. The # of fd is around 250 in normal time. However, when the problem appeared, it will be raised to 1500 and then back to normal. It sounds funny, right? Do you have any idea what's going on? ======================== The CPU graph of one of the web server.

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  • Java - Is Set.contains() broken on OpenJDK 6?

    - by Peter
    Hey, I've come across a really strange problem. I have written a simple Deck class which represents a standard 52 card deck of playing cards. The class has a method missingCards() which returns the set of all cards which have been drawn from the deck. If I try and compare two identical sets of missing cards using .equals() I'm told they are different, and if I check to see if a set contains an element that I know is there using .contains() I am returned false. Here is my test code: public void testMissingCards() { Deck deck = new Deck(true); Set<Card> drawnCards = new HashSet<Card>(); drawnCards.add(deck.draw()); drawnCards.add(deck.draw()); drawnCards.add(deck.draw()); Set<Card> missingCards = deck.missingCards(); System.out.println(drawnCards); System.out.println(missingCards); Card c1 = null; for (Card c : drawnCards){ c1 = c; } System.out.println("C1 is "+c1); for (Card c : missingCards){ System.out.println("C is "+c); System.out.println("Does c1.equal(c) "+c1.equals(c)); System.out.println("Does c.equal(c1) "+c.equals(c1)); } System.out.println("Is c1 in missingCards "+missingCards.contains(c1)); assertEquals("Deck confirm missing cards",drawnCards,missingCards); } (Edit: Just for clarity I added the two loops after I noticed the test failing. The first loop pulls out a card from drawnCards and then this card is checked against every card in missingCards - it always matches one, so that card must be contained in missingCards. However, missingCards.contains() fails) And here is an example of it's output: [5C, 2C, 2H] [2C, 5C, 2H] C1 is 2H C is 2C Does c1.equal(c) false Does c.equal(c1) false C is 5C Does c1.equal(c) false Does c.equal(c1) false C is 2H Does c1.equal(c) true Does c.equal(c1) true Is c1 in missingCards false I am completely sure that the implementation of .equals on my card class is correct and, as you can see from the output it does work! What is going on here? Cheers, Pete

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  • Trying to find a PHP5 API-based embeddable CMS

    - by StrangeElement
    I've been making the rounds for a CMS that I can use as an API, in a sort of "embedded" mode. I mean by this that I don't want the CMS to do any logic or presentation. I want it to be used as an API, which I can then use within an existing site. I don't want to be tied to the architecture of the CMS. A good example of this is NC-CMS (http://www.nconsulting.ca/nc-cms/). All it needs is an include at the top, then wherever editable content is desired it's only a function call with a unique label. It's also perfect in the sense that it allows to differentiate between small strings (like titles, labels) and texts (which require a rich-text editor). It's the only CMS I found that fits this description, but it is a little too light as it does not handle site structure. I need to be able to allow my client to add pages, choosing an existing template for the layout. A minimal back-end is required. Wordpress also fits some requirements in that it handles only content editing and allows freedom for the themes by letting them call the content where and how they want it. But it is article-based and backwards, in that it embeds sites (as themes) within its structure, rather than being embeddable in sites like NC. It's funny how checking out all the CMS out there, almost all of them claim that most CMS are not self-sufficient, that they do not handle application logic, while (almost) every single on I found with only one exception do so. Many are mostly article-based blog engines, which does not fit my need. I would appreciate any CMS that fits the general description.

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  • Avoiding a fork()/SIGCHLD race condition

    - by larry
    Please consider the following fork()/SIGCHLD pseudo-code. // main program excerpt for (;;) { if ( is_time_to_make_babies ) { pid = fork(); if (pid == -1) { /* fail */ } else if (pid == 0) { /* child stuff */ print "child started" exit } else { /* parent stuff */ print "parent forked new child ", pid children.add(pid); } } } // SIGCHLD handler sigchld_handler(signo) { while ( (pid = wait(status, WNOHANG)) > 0 ) { print "parent caught SIGCHLD from ", pid children.remove(pid); } } In the above example there's a race-condition. It's possible for "/* child stuff */" to finish before "/* parent stuff */" starts which can result in a child's pid being added to the list of children after it's exited, and never being removed. When the time comes for the app to close down, the parent will wait endlessly for the already-finished child to finish. One solution I can think of to counter this is to have two lists: started_children and finished_children. I'd add to started_children in the same place I'm adding to children now. But in the signal handler, instead of removing from children I'd add to finished_children. When the app closes down, the parent can simply wait until the difference between started_children and finished_children is zero. Another possible solution I can think of is using shared-memory, e.g. share the parent's list of children and let the children .add and .remove themselves? But I don't know too much about this. EDIT: Another possible solution, which was the first thing that came to mind, is to simply add a sleep(1) at the start of /* child stuff */ but that smells funny to me, which is why I left it out. I'm also not even sure it's a 100% fix. So, how would you correct this race-condition? And if there's a well-established recommended pattern for this, please let me know! Thanks.

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  • Why is a NullReferenceException thrown when a ToolStrip button is clicked twice with code in the `Click` event handler?

    - by Patrick
    I created a clean WindowsFormsApplication solution, added a ToolStrip to the main form, and placed one button on it. I've added also an OpenFileDialog, so that the Click event of the ToolStripButton looks like the following: private void toolStripButton1_Click(object sender, EventArgs e) { openFileDialog1.ShowDialog(); } I didn't change any other properties or events. The funny thing is that when I double-click the ToolStripButton (the second click must be quite fast, before the dialog opens), then cancel both dialogs (or choose a file, it doesn't really matter) and then click in the client area of main form, a NullReferenceException crashes the application (error details attached at the end of the post). Please note that the Click event is implemented while DoubleClick is not. What's even more strange that when the OpenFileDialog is replaced by any user-implemented form, the ToolStripButton blocks from being clicked twice. I'm using VS2008 with .NET3.5. I didn't change many options in VS (only fontsize, workspace folder and line numbering). Does anyone know how to solve this? It is 100% replicable on my machine, is it on others too? One solution that I can think of is disabling the button before calling OpenFileDialog.ShowDialog() and then enabling the button back (but it's not nice). Any other ideas? And now the promised error details: System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="System.Windows.Forms" StackTrace: at System.Windows.Forms.NativeWindow.WindowClass.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) at System.Windows.Forms.UnsafeNativeMethods.PeekMessage(MSG& msg, HandleRef hwnd, Int32 msgMin, Int32 msgMax, Int32 remove) at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(Form mainForm) at WindowsFormsApplication1.Program.Main() w C:\Users\Marchewek\Desktop\Workspaces\VisualStudio\WindowsFormsApplication1\Program.cs:line 20 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException:

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  • NullPointerException with static variables

    - by tomekK
    I just hit very strange (to me) behaviour of java. I have following classes: public abstract class Unit { public static final Unit KM = KMUnit.INSTANCE; public static final Unit METERS = MeterUnit.INSTANCE; protected Unit() { } public abstract double getValueInUnit(double value, Unit unit); protected abstract double getValueInMeters(double value); } And: public class KMUnit extends Unit { public static final Unit INSTANCE = new KMUnit(); private KMUnit() { } //here are abstract methods overriden } public class MeterUnit extends Unit { public static final Unit INSTANCE = new MeterUnit(); private MeterUnit() { } ///abstract methods overriden } And my test case: public class TestMetricUnits extends TestCase { @Test public void testConversion() { System.out.println("Unit.METERS: " + Unit.METERS); System.out.println("Unit.KM: " + Unit.KM); double meters = Unit.KM.getValueInUnit(102.11, Unit.METERS); assertEquals(0.10211, meters, 0.00001); } } 1) MKUnit and MeterUnit are both singletons initialized statically, so during class loading. Constructors are private, so they can't be initialized anywhere else. 2) Unit class contains static final references to MKUnit.INSTANCE and MeterUnit.INSTANCE I would expect that: KMUnit class is loaded and instance is created. MeterUnit class is loaded and instance is created. Unit class is loaded and both KM and METERS variable are initialized, they are final so they cant be changed. But when I run my test case in console with maven my result is: T E S T S Running de.audi.echargingstations.tests.TestMetricUnits Unit.METERS: m Unit.KM: null Tests run: 3, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.089 sec <<< FAILURE! - in de.audi.echargingstations.tests.TestMetricUnits testConversion(de.audi.echargingstations.tests.TestMetricUnits) Time elapsed: 0.011 sec <<< ERROR! java.lang.NullPointerException: null at de.audi.echargingstations.tests.TestMetricUnits.testConversion(TestMetricUnits.java:29) Results : Tests in error: TestMetricUnits.testConversion:29 NullPointer And the funny part is that, when I run this test from eclipse via JUnit runner everything is fine, I have no NullPointerException and in console I have: Unit.METERS: m Unit.KM: km So the question is: what can be the reason that KM variable in Unit is null (and in the same time METERS is not null)

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  • Specifying both multiple targets and multiple build files with ant or subant in 1.6

    - by Paul Marshall
    I'm trying to unify a build process, running one build to get multiple packages. My first shot at this is just having a central build script call <ant or <subant on each project's build.xml file. I'm using Ant 1.6, and I've run into a funny problem: either I use the <ant task, and I can specify multiple targets but not multiple build files, or I use the <subant task, and I can specify multiple build files but not multiple targets. I realize there's a few solutions here already: Just upgrade to Ant 1.7 already; <antcall can do multiple targets there. Edit the separate project build files to have a variety of top-level targets, so I can call each individual file with just one target, and use <antcall. Copy-paste a lot of <ant tasks, with a little help from <macrodef to help the sanity. Is there something I've missed, that will allow me to do what I want from this single central build.xml without a) editing individual project files, b) writing lots of repetitive code, or c) upgrading Ant, and that d) doesn't require editing every time I add a new project?

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  • Am I a discoverer of a bug in the WPF engine?

    - by bitbonk
    We have a MFC 8 application compiled with /CLR that contains a larger amount of Windows Forms UserControls wich again contain WPF user controls using ElementHost. Due to the architecture of our software we can not use HwndHost directly. We observed an extremely strange behavior here that we can not make any sense of: When the CPU load is very high during startup of the application and there are a lot live of ElementHost instances, the whole property engine completely stops working. For example animations that usually just work fine now never update the values of the bound properties, they just stay at some random value after startup. When I set a property that is not bound to anything the value is correctly stored in the dependency property (calling the getter returns the new value) but the visual representation never reflects that. I set the background to red but the background color does not change. We tested this on a lot of different machines all running Windows XP SP2 and it is pretty reproducible. The funny thing here is, that there is in fact one situation where the bound properties actually pickup a new value from the animation and the visual gets updated based on the property values. It is when I resize the ElementHost or when I hide and reshow the parent native control. As soon as I do this, properties that are bound to an animation pickup a new value and the visuals rerender based on the new property values - but just once - if I want to see another update I have to resize the ElementHost. Do you have any explanation of what could be happening here or how I could approach this problem to find it out? What can I do to debug this? Is there a way I can get more information about what WPF actually does or where WPF might have crashed? To me it currently seems like a bug in WPF itself since it only happens at high CPU load at startup.

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  • How should I launch a Portable Python Tkinter application on Windows without ugliness?

    - by Andrew
    I've written a simple GUI program in python using Tkinter. Let's call this program 'gui.py'. My users run 'gui.py' on Windows machines from a USB key using Portable Python; installing anything on the host machine is undesirable. I'd like my users to run 'gui.py' by double-clicking an icon at the root of the USB key. My users don't care what python is, and they don't want to use a command prompt if they don't have to. I don't want them to have to care what drive letter the USB key is assigned. I'd like this to work on XP, Vista, and 7. My first ugly solution was to create a shortcut in the root directory of the USB key, and set the "Target" property of the shortcut to something like "(root)\App\pythonw.exe (root)\App\gui.py", but I couldn't figure out how to do a relative path in a windows shortcut, and using an absolute path like "E:" seems fragile. My next solution was to create a .bat script in the root directory of the USB key, something like this: @echo off set basepath=%~dp0 "%basepath%App\pythonw.exe" "%basepath%\App\gui.py" This doesn't seem to care what drive letter the USB key is assigned, but it does leave a DOS window open while my program runs. Functional, but ugly. Next I tried a .bat script like this: @echo off set basepath=%~dp0 start "" "%basepath%App\pythonw.exe" "%basepath%\App\gui.py" (See here for an explanation of the funny quoting) Now, the DOS window briefly flashes on screen before my GUI opens. Less ugly! Still ugly. How do real men deal with this problem? What's the least ugly way to start a python Tkinter GUI on a Windows machine from a USB stick?

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