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• g++ symbol versioning. Set it to GCC_3.0 using version 4 of g++

  - by Ismael

  Hi all I need to implemente a Java class which uses JNI to control a fiscal printer in XUbuntu 8.10 with sun-java6-jdk installed. The structure is the following: EpsonDriver.java loads libEpson.so libEpson is linked dynamically with EpsonFiscalProtocol.so ( provided by Epson, no source available ) and pthread I use javah to generate the header file, and the code compiles. Then I put the libEpson.so in $JAVA_HOME/jre/lib/i386, and EpsonDriver.java uses an static initializar System.loadLibrary("libEpson") That part works, however, when I try to use any of the methods I get an unsatisfiedLinkError exception. Some time ago, a coworker did a version that works, and using objdump -Dslx I got the following: Program Header: LOAD off 0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**12 filesz 0x0000ccc4 memsz 0x0000ccc4 flags r-x LOAD off 0x0000d000 vaddr 0x0000d000 paddr 0x0000d000 align 2**12 filesz 0x00000250 memsz 0x00044a5c flags rw- DYNAMIC off 0x0000d014 vaddr 0x0000d014 paddr 0x0000d014 align 2**2 filesz 0x000000f0 memsz 0x000000f0 flags rw- NOTE off 0x000000d4 vaddr 0x000000d4 paddr 0x000000d4 align 2**2 filesz 0x00000024 memsz 0x00000024 flags r-- STACK off 0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**2 filesz 0x00000000 memsz 0x00000000 flags rw- Dynamic Section: NEEDED EpsonFiscalProtocol.so NEEDED libpthread.so.0 NEEDED libstdc++.so.6 NEEDED libm.so.6 NEEDED libc.so.6 SONAME libcom_tichile_jpos_EpsonSerialDriver.so INIT 0x00007254 FINI 0x0000ba08 GNU_HASH 0x000000f8 STRTAB 0x00001f50 SYMTAB 0x00000ae0 STRSZ 0x00002384 SYMENT 0x00000010 PLTGOT 0x0000d108 PLTRELSZ 0x00000008 PLTREL 0x00000011 JMPREL 0x0000724c REL 0x000045c4 RELSZ 0x00002c88 RELENT 0x00000008 TEXTREL 0x00000000 VERNEED 0x00004564 VERNEEDNUM 0x00000002 VERSYM 0x000042d4 RELCOUNT 0x000000ac Version References: required from libstdc++.so.6: 0x056bafd3 0x00 05 CXXABI_1.3 0x08922974 0x00 04 GLIBCXX_3.4 required from libc.so.6: 0x0b792650 0x00 03 GCC_3.0 0x0d696910 0x00 02 GLIBC_2.0 In the recently compiled file I get: Program Header: LOAD off 0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**12 filesz 0x00005300 memsz 0x00005300 flags r-x LOAD off 0x00005300 vaddr 0x00006300 paddr 0x00006300 align 2**12 filesz 0x00000274 memsz 0x00010314 flags rw- DYNAMIC off 0x00005314 vaddr 0x00006314 paddr 0x00006314 align 2**2 filesz 0x000000e0 memsz 0x000000e0 flags rw- EH_FRAME off 0x00004a00 vaddr 0x00004a00 paddr 0x00004a00 align 2**2 filesz 0x00000154 memsz 0x00000154 flags r-- Dynamic Section: NEEDED libstdc++.so.5 NEEDED libm.so.6 NEEDED libgcc_s.so.1 NEEDED libc.so.6 SONAME EpsonFiscalProtocol.so INIT 0x00001cb4 FINI 0x00004994 HASH 0x000000b4 STRTAB 0x00000da4 SYMTAB 0x000004f4 STRSZ 0x00000acf SYMENT 0x00000010 PLTGOT 0x0000640c PLTRELSZ 0x00000270 PLTREL 0x00000011 JMPREL 0x00001a44 REL 0x000019dc RELSZ 0x00000068 RELENT 0x00000008 VERNEED 0x0000198c VERNEEDNUM 0x00000002 VERSYM 0x00001874 RELCOUNT 0x00000004 Version References: required from libstdc++.so.5: 0x056bafd2 0x00 04 CXXABI_1.2 required from libc.so.6: 0x09691f73 0x00 03 GLIBC_2.1.3 0x0d696910 0x00 02 GLIBC_2.0 So I suspect the main diference is the GCC_3.0 symbol I compile libcom_tichile_EpsonSerialDriver.so with the following command ( from memory as I not at work right now ) g++ -Wl,-soname=.... -shared -I/*jni libraries*/ -o libcom_tichile_jpos_EpsonSerialDriver -lEpsonFiscalProtocol -lpthread Is there any way to tell g++ to use that symbol version? Or any idea in how to make it work? EDIT: I have another non-working version with the followin dump: Program Header: LOAD off 0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**12 filesz 0x0000bf68 memsz 0x0000bf68 flags r-x LOAD off 0x0000cc0c vaddr 0x0000cc0c paddr 0x0000cc0c align 2**12 filesz 0x000005e8 memsz 0x00044df0 flags rw- DYNAMIC off 0x0000cc20 vaddr 0x0000cc20 paddr 0x0000cc20 align 2**2 filesz 0x000000f8 memsz 0x000000f8 flags rw- EH_FRAME off 0x0000b310 vaddr 0x0000b310 paddr 0x0000b310 align 2**2 filesz 0x000002bc memsz 0x000002bc flags r-- STACK off 0x00000000 vaddr 0x00000000 paddr 0x00000000 align 2**2 filesz 0x00000000 memsz 0x00000000 flags rw- RELRO off 0x0000cc0c vaddr 0x0000cc0c paddr 0x0000cc0c align 2**0 filesz 0x000003f4 memsz 0x000003f4 flags r-- Dynamic Section: NEEDED EpsonFiscalProtocol.so NEEDED libpthread.so.0 NEEDED libstdc++.so.6 NEEDED libm.so.6 NEEDED libgcc_s.so.1 NEEDED libc.so.6 SONAME libcom_tichile_jpos_EpsonSerialDriver.so INIT 0x000055d8 FINI 0x0000a968 HASH 0x000000f4 GNU_HASH 0x00000a30 STRTAB 0x00002870 SYMTAB 0x00001410 STRSZ 0x00002339 SYMENT 0x00000010 PLTGOT 0x0000cff4 PLTRELSZ 0x00000168 PLTREL 0x00000011 JMPREL 0x00005470 REL 0x00004ea8 RELSZ 0x000005c8 RELENT 0x00000008 VERNEED 0x00004e38 VERNEEDNUM 0x00000002 VERSYM 0x00004baa RELCOUNT 0x00000001 Version References: required from libstdc++.so.6: 0x056bafd3 0x00 05 CXXABI_1.3 0x08922974 0x00 03 GLIBCXX_3.4 required from libc.so.6: 0x09691f73 0x00 06 GLIBC_2.1.3 0x0d696914 0x00 04 GLIBC_2.4 0x0d696910 0x00 02 GLIBC_2.0 Now I think the main difference is in the GCC_3.0 symbol/ABI EDIT: Luckily, a coworker found a way to talk to the printer using Java

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• Symfony 1.4/ Doctrine; n-m relation data cannot be accessed in template (indexSuccess)

  - by chandimak

  I have a database with 3 tables. It's a simple n-m relationship. Student, Course and StudentHasCourse to handle n-m relationship. I post the schema.yml for reference, but it would not be really necessary. Course: connection: doctrine tableName: course columns: id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false name: type: string(45) fixed: false unsigned: false primary: false notnull: false autoincrement: false relations: StudentHasCourse: local: id foreign: course_id type: many Student: connection: doctrine tableName: student columns: id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false registration_details: type: string(45) fixed: false unsigned: false primary: false notnull: false autoincrement: false name: type: string(30) fixed: false unsigned: false primary: false notnull: false autoincrement: false relations: StudentHasCourse: local: id foreign: student_id type: many StudentHasCourse: connection: doctrine tableName: student_has_course columns: student_id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false course_id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false result: type: string(1) fixed: true unsigned: false primary: false notnull: false autoincrement: false relations: Course: local: course_id foreign: id type: one Student: local: student_id foreign: id type: one Then, I get data from tables in executeIndex() from the following query. $q_info = Doctrine_Query::create() ->select('s.*, shc.*, c.*') ->from('Student s') ->leftJoin('s.StudentHasCourse shc') ->leftJoin('shc.Course c') ->where('c.id = 1'); $this->infos = $q_info->execute(); Then I access data by looping through in indexSuccess.php. But, in indexSuccess I can only access data from the table Student. <?php foreach ($infos as $info): ?> <?php echo $info->getId(); ?> <?php echo $info->getName(); ?> <?php endforeach; ?> I expected, that I could access StudentHasCourse data and Course data like the following. But, it generates an error. <?php echo $info->getStudentHasCourse()->getResult()?> <?php echo $info->getStudentHasCourse()->getCourse()->getName()?> The first statement gives a warning; Warning: call_user_func_array() expects parameter 1 to be a valid callback, class 'Doctrine_Collection' does not have a method 'getCourse' in D:\wamp\bin\php\php5.3.5\PEAR\pear\symfony\escaper\sfOutputEscaperObjectDecorator.class.php on line 64 And the second statement gives the above warning and the following error; Fatal error: Call to a member function getName() on a non-object in D:\wamp\www\sam\test_doc_1\apps\frontend\modules\registration\templates\indexSuccess.php on line 5 When I check the query from the Debug toolbar it appears as following and it gives all data I want. SELECT s.id AS s__id, s.registration_details AS s__registration_details, s.name AS s__name, s2.student_id AS s2__student_id, s2.course_id AS s2__course_id, s2.result AS s2__result, c.id AS c__id, c.name AS c__name FROM student s LEFT JOIN student_has_course s2 ON s.id = s2.student_id LEFT JOIN course c ON s2.course_id = c.id WHERE (c.id = 1) Though the question is short, as all the information mentioned it became so long. It's highly appreciated if someone can help me out to solve this. What I require is to access the data from StudentHasCourse and Course. If those data cannot be accessed by this design and this query, any other methodology is also appreciated.

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• Spring Security and the Synchronizer Token J2EE pattern, problem when authentication fails.

  - by dfuse

  Hey, we are using Spring Security 2.0.4. We have a TransactionTokenBean which generates a unique token each POST, the bean is session scoped. The token is used for the duplicate form submission problem (and security). The TransactionTokenBean is called from a Servlet filter. Our problem is the following, after a session timeout occured, when you do a POST in the application Spring Security redirects to the logon page, saving the original request. After logging on again the TransactionTokenBean is created again, since it is session scoped, but then Spring forwards to the originally accessed url, also sending the token that was generated at that time. Since the TransactionTokenBean is created again, the tokens do not match and our filter throws an Exception. I don't quite know how to handle this elegantly, (or for that matter, I can't even fix it with a hack), any ideas? This is the code of the TransactionTokenBean: public class TransactionTokenBean implements Serializable { public static final int TOKEN_LENGTH = 8; private RandomizerBean randomizer; private transient Logger logger; private String expectedToken; public String getUniqueToken() { return expectedToken; } public void init() { resetUniqueToken(); } public final void verifyAndResetUniqueToken(String actualToken) { verifyUniqueToken(actualToken); resetUniqueToken(); } public void resetUniqueToken() { expectedToken = randomizer.getRandomString(TOKEN_LENGTH, RandomizerBean.ALPHANUMERICS); getLogger().debug("reset token to: " + expectedToken); } public void verifyUniqueToken(String actualToken) { if (getLogger().isDebugEnabled()) { getLogger().debug("verifying token. expected=" + expectedToken + ", actual=" + actualToken); } if (expectedToken == null || actualToken == null || !isValidToken(actualToken)) { throw new IllegalArgumentException("missing or invalid transaction token"); } if (!expectedToken.equals(actualToken)) { throw new InvalidTokenException(); } } private boolean isValidToken(String actualToken) { return StringUtils.isAlphanumeric(actualToken); } public void setRandomizer(RandomizerBean randomizer) { this.randomizer = randomizer; } private Logger getLogger() { if (logger == null) { logger = Logger.getLogger(TransactionTokenBean.class); } return logger; } } and this is the Servlet filter (ignore the Ajax stuff): public class SecurityFilter implements Filter { static final String AJAX_TOKEN_PARAM = "ATXTOKEN"; static final String TOKEN_PARAM = "TXTOKEN"; private WebApplicationContext webApplicationContext; private Logger logger = Logger.getLogger(SecurityFilter.class); public void init(FilterConfig config) { setWebApplicationContext(WebApplicationContextUtils.getWebApplicationContext(config.getServletContext())); } public void destroy() { } public void doFilter(ServletRequest req, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) req; if (isPostRequest(request)) { if (isAjaxRequest(request)) { log("verifying token for AJAX request " + request.getRequestURI()); getTransactionTokenBean(true).verifyUniqueToken(request.getParameter(AJAX_TOKEN_PARAM)); } else { log("verifying and resetting token for non-AJAX request " + request.getRequestURI()); getTransactionTokenBean(false).verifyAndResetUniqueToken(request.getParameter(TOKEN_PARAM)); } } chain.doFilter(request, response); } private void log(String line) { if (logger.isDebugEnabled()) { logger.debug(line); } } private boolean isPostRequest(HttpServletRequest request) { return "POST".equals(request.getMethod().toUpperCase()); } private boolean isAjaxRequest(HttpServletRequest request) { return request.getParameter("AJAXREQUEST") != null; } private TransactionTokenBean getTransactionTokenBean(boolean ajax) { return (TransactionTokenBean) webApplicationContext.getBean(ajax ? "ajaxTransactionTokenBean" : "transactionTokenBean"); } void setWebApplicationContext(WebApplicationContext context) { this.webApplicationContext = context; } }

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• Can this be improved? Scrubbing of dangerous html tags.

  - by chobo2

  I been finding that for something that I consider pretty import there is very little information or libraries on how to deal with this problem. I found this while searching. I really don't know all the million ways that a hacker could try to insert the dangerous tags. I have a rich html editor so I need to keep non dangerous tags but strip out bad ones. So is this script missing anything? It uses html agility pack. public string ScrubHTML(string html) { HtmlDocument doc = new HtmlDocument(); doc.LoadHtml(html); //Remove potentially harmful elements HtmlNodeCollection nc = doc.DocumentNode.SelectNodes("//script|//link|//iframe|//frameset|//frame|//applet|//object|//embed"); if (nc != null) { foreach (HtmlNode node in nc) { node.ParentNode.RemoveChild(node, false); } } //remove hrefs to java/j/vbscript URLs nc = doc.DocumentNode.SelectNodes("//a[starts-with(translate(@href, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'javascript')]|//a[starts-with(translate(@href, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'jscript')]|//a[starts-with(translate(@href, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'vbscript')]"); if (nc != null) { foreach (HtmlNode node in nc) { node.SetAttributeValue("href", "#"); } } //remove img with refs to java/j/vbscript URLs nc = doc.DocumentNode.SelectNodes("//img[starts-with(translate(@src, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'javascript')]|//img[starts-with(translate(@src, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'jscript')]|//img[starts-with(translate(@src, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'vbscript')]"); if (nc != null) { foreach (HtmlNode node in nc) { node.SetAttributeValue("src", "#"); } } //remove on<Event> handlers from all tags nc = doc.DocumentNode.SelectNodes("//*[@onclick or @onmouseover or @onfocus or @onblur or @onmouseout or @ondoubleclick or @onload or @onunload]"); if (nc != null) { foreach (HtmlNode node in nc) { node.Attributes.Remove("onFocus"); node.Attributes.Remove("onBlur"); node.Attributes.Remove("onClick"); node.Attributes.Remove("onMouseOver"); node.Attributes.Remove("onMouseOut"); node.Attributes.Remove("onDoubleClick"); node.Attributes.Remove("onLoad"); node.Attributes.Remove("onUnload"); } } // remove any style attributes that contain the word expression (IE evaluates this as script) nc = doc.DocumentNode.SelectNodes("//*[contains(translate(@style, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), 'expression')]"); if (nc != null) { foreach (HtmlNode node in nc) { node.Attributes.Remove("stYle"); } } return doc.DocumentNode.WriteTo(); } Edit 2 people have suggested whitelisting. I actually like the idea of whitelisting but never actually did it because no one can actually tell me how to do it in C# and I can't even really find tutorials for how to do it in c#(the last time I looked. I will check it out again). How do you make a white list? Is it just a list collection? How do you actual parse out all html tags, script tags and every other tag? Once you have the tags how do you determine which ones are allowed? Compare them to you list collection? But what happens if the content is coming in and has like 100 tags and you have 50 allowed. You got to compare each of those 100 tag by 50 allowed tags. Thats quite a bit to go through and could be slow. Once you found a invalid tag how do you remove it? I don't really want to reject a whole set of text if one tag was found to be invalid. I rather remove and insert the rest. Should I be using html agility pack?

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• How do I maximize code coverage?

  - by naivedeveloper

  Hey all, the following is a snippet of code taken from the unix ptx utility. I'm attempting to maximize code coverage on this utility, but I am unable to reach the indicated portion of code. Admittedly, I'm not as strong in my C skills as I used to be. The portion of code is indicated with comments, but it is towards the bottom of the block. if (used_length == allocated_length) { allocated_length += (1 << SWALLOW_REALLOC_LOG); block->start = (char *) xrealloc (block->start, allocated_length); } Any help interpreting the indicated portion in order to cover that block would be greatly appreciated. /* Reallocation step when swallowing non regular files. The value is not the actual reallocation step, but its base two logarithm. */ #define SWALLOW_REALLOC_LOG 12 static void swallow_file_in_memory (const char *file_name, BLOCK *block) { int file_handle; /* file descriptor number */ struct stat stat_block; /* stat block for file */ size_t allocated_length; /* allocated length of memory buffer */ size_t used_length; /* used length in memory buffer */ int read_length; /* number of character gotten on last read */ /* As special cases, a file name which is NULL or "-" indicates standard input, which is already opened. In all other cases, open the file from its name. */ bool using_stdin = !file_name || !*file_name || strcmp (file_name, "-") == 0; if (using_stdin) file_handle = STDIN_FILENO; else if ((file_handle = open (file_name, O_RDONLY)) < 0) error (EXIT_FAILURE, errno, "%s", file_name); /* If the file is a plain, regular file, allocate the memory buffer all at once and swallow the file in one blow. In other cases, read the file repeatedly in smaller chunks until we have it all, reallocating memory once in a while, as we go. */ if (fstat (file_handle, &stat_block) < 0) error (EXIT_FAILURE, errno, "%s", file_name); if (S_ISREG (stat_block.st_mode)) { size_t in_memory_size; block->start = (char *) xmalloc ((size_t) stat_block.st_size); if ((in_memory_size = read (file_handle, block->start, (size_t) stat_block.st_size)) != stat_block.st_size) { error (EXIT_FAILURE, errno, "%s", file_name); } block->end = block->start + in_memory_size; } else { block->start = (char *) xmalloc ((size_t) 1 << SWALLOW_REALLOC_LOG); used_length = 0; allocated_length = (1 << SWALLOW_REALLOC_LOG); while (read_length = read (file_handle, block->start + used_length, allocated_length - used_length), read_length > 0) { used_length += read_length; /* Cannot cover from this point...*/ if (used_length == allocated_length) { allocated_length += (1 << SWALLOW_REALLOC_LOG); block->start = (char *) xrealloc (block->start, allocated_length); } /* ...to this point. */ } if (read_length < 0) error (EXIT_FAILURE, errno, "%s", file_name); block->end = block->start + used_length; } /* Close the file, but only if it was not the standard input. */ if (! using_stdin && close (file_handle) != 0) error (EXIT_FAILURE, errno, "%s", file_name); }

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• Boost::Spirit::Qi autorules -- avoiding repeated copying of AST data structures

  - by phooji

  I've been using Qi and Karma to do some processing on several small languages. Most of the grammars are pretty small (20-40 rules). I've been able to use autorules almost exclusively, so my parse trees consist entirely of variants, structs, and std::vectors. This setup works great for the common case: 1) parse something (Qi), 2) make minor manipulations to the parse tree (visitor), and 3) output something (Karma). However, I'm concerned about what will happen if I want to make complex structural changes to a syntax tree, like moving big subtrees around. Consider the following toy example: A grammar for s-expr-style logical expressions that uses autorules... // Inside grammar class; rule names match struct names... pexpr %= pand | por | var | bconst; pand %= lit("(and ") >> (pexpr % lit(" ")) >> ")"; por %= lit("(or ") >> (pexpr % lit(" ")) >> ")"; pnot %= lit("(not ") >> pexpr >> ")"; ... which leads to parse tree representation that looks like this... struct var { std::string name; }; struct bconst { bool val; }; struct pand; struct por; struct pnot; typedef boost::variant<bconst, var, boost::recursive_wrapper<pand>, boost::recursive_wrapper<por>, boost::recursive_wrapper<pnot> > pexpr; struct pand { std::vector<pexpr> operands; }; struct por { std::vector<pexpr> operands; }; struct pnot { pexpr victim; }; // Many Fusion Macros here Suppose I have a parse tree that looks something like this: pand / ... \ por por / \ / \ var var var var (The ellipsis means 'many more children of similar shape for pand.') Now, suppose that I want negate each of the por nodes, so that the end result is: pand / ... \ pnot pnot | | por por / \ / \ var var var var The direct approach would be, for each por subtree: - create pnot node (copies por in construction); - re-assign the appropriate vector slot in the pand node (copies pnot node and its por subtree). Alternatively, I could construct a separate vector, and then replace (swap) the pand vector wholesale, eliminating a second round of copying. All of this seems cumbersome compared to a pointer-based tree representation, which would allow for the pnot nodes to be inserted without any copying of existing nodes. My question: Is there a way to avoid copy-heavy tree manipulations with autorule-compliant data structures? Should I bite the bullet and just use non-autorules to build a pointer-based AST (e.g., http://boost-spirit.com/home/2010/03/11/s-expressions-and-variants/)?

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• Increasing speed of python code

  - by Curious2learn

  Hi, I have some python code that has many classes. I used cProfile to find that the total time to run the program is 68 seconds. I found that the following function in a class called Buyers takes about 60 seconds of those 68 seconds. I have to run the program about 100 times, so any increase in speed will help. Can you suggest ways to increase the speed by modifying the code? If you need more information that will help, please let me know. def qtyDemanded(self, timePd, priceVector): '''Returns quantity demanded in period timePd. In addition, also updates the list of customers and non-customers. Inputs: timePd and priceVector Output: count of people for whom priceVector[-1] < utility ''' ## Initialize count of customers to zero ## Set self.customers and self.nonCustomers to empty lists price = priceVector[-1] count = 0 self.customers = [] self.nonCustomers = [] for person in self.people: if person.utility >= price: person.customer = 1 self.customers.append(person) else: person.customer = 0 self.nonCustomers.append(person) return len(self.customers) self.people is a list of person objects. Each person has customer and utility as its attributes. EDIT - responsed added ------------------------------------- Thanks so much for the suggestions. Here is the response to some questions and suggestions people have kindly made. I have not tried them all, but will try others and write back later. (1) @amber - the function is accessed 80,000 times. (2) @gnibbler and others - self.people is a list of Person objects in memory. Not connected to a database. (3) @Hugh Bothwell cumtime taken by the original function - 60.8 s (accessed 80000 times) cumtime taken by the new function with local function aliases as suggested - 56.4 s (accessed 80000 times) (4) @rotoglup and @Martin Thomas I have not tried your solutions yet. I need to check the rest of the code to see the places where I use self.customers before I can make the change of not appending the customers to self.customers list. But I will try this and write back. (5) @TryPyPy - thanks for your kind offer to check the code. Let me first read a little on the suggestions you have made to see if those will be feasible to use. EDIT 2 Some suggested that since I am flagging the customers and noncustomers in the self.people, I should try without creating separate lists of self.customers and self.noncustomers using append. Instead, I should loop over the self.people to find the number of customers. I tried the following code and timed both functions below f_w_append and f_wo_append. I did find that the latter takes less time, but it is still 96% of the time taken by the former. That is, it is a very small increase in the speed. @TryPyPy - The following piece of code is complete enough to check the bottleneck function, in case your offer is still there to check it with other compilers. Thanks again to everyone who replied. import numpy class person(object): def __init__(self, util): self.utility = util self.customer = 0 class population(object): def __init__(self, numpeople): self.people = [] self.cus = [] self.noncus = [] numpy.random.seed(1) utils = numpy.random.uniform(0, 300, numpeople) for u in utils: per = person(u) self.people.append(per) popn = population(300) def f_w_append(): '''Function with append''' P = 75 cus = [] noncus = [] for per in popn.people: if per.utility >= P: per.customer = 1 cus.append(per) else: per.customer = 0 noncus.append(per) return len(cus) def f_wo_append(): '''Function without append''' P = 75 for per in popn.people: if per.utility >= P: per.customer = 1 else: per.customer = 0 numcustomers = 0 for per in popn.people: if per.customer == 1: numcustomers += 1 return numcustomers

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• WCF using windows service

  - by Lijo

  Hi, I am creating a WCF service which is to be hosted in Windows Service. I created a console application as follows I went to management console (services.msc) and started the service. But I got the following error "The LijosWindowsService service on Local Computer started and then stopped. Some services stop automatically if they have no work to do, for example, the Performance Logs and Alerts service" I went to the event viewer and got the following "Service cannot be started. System.InvalidOperationException: Service 'Lijo.Samples.WeatherService' has zero application (non-infrastructure) endpoints. This might be because no configuration file was found for your application, or because no service element matching the service name could be found in the configuration file, or because no endpoints were defined in the service element." Could you please let me know what is the missing link here? File name [LijosService.cs] using System.ComponentModel; using System.ServiceModel; using System.ServiceProcess; using System.Configuration; using System.Configuration.Install; namespace Lijo.Samples { [ServiceContract(Namespace = "http://Lijo.Samples")] public interface IWeather { [OperationContract] double Add(double n1, double n2); } public class WeatherService : IWeather { public double Add(double n1, double n2) { double result = n1 + n2; return result; } } public class MyWindowsService : ServiceBase { public ServiceHost serviceHost = null; public MyWindowsService() { // Windows Service name ServiceName = "LijosWindowsService"; } public static void Main() { ServiceBase.Run(new MyWindowsService()); } protected override void OnStart(string[] args) { if (serviceHost != null) { serviceHost.Close(); } serviceHost = new ServiceHost(typeof(WeatherService)); serviceHost.Open(); } protected override void OnStop() { if (serviceHost != null) { serviceHost.Close(); serviceHost = null; } } } // ProjectInstaller [RunInstaller(true)] public class ProjectInstaller : Installer { private ServiceProcessInstaller myProcess; private ServiceInstaller myService; public ProjectInstaller() { myProcess = new ServiceProcessInstaller(); myProcess.Account = ServiceAccount.LocalSystem; myService = new ServiceInstaller(); myService.ServiceName = "LijosWindowsService"; Installers.Add(myProcess); Installers.Add(myService); } } } App.config <?xml version="1.0" encoding="utf-8" ?> <configuration> <system.serviceModel> <services> <service name="Lijo.Samples.WeatherService" behaviorConfiguration="WeatherServiceBehavior"> <host> <baseAddresses> <add baseAddress="http://localhost:8000/ServiceModelSamples/LijosService"/> </baseAddresses> </host> <endpoint address="" binding="wsHttpBinding" contract="Lijo.Samples.IWeather" /> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services> <behaviors> <serviceBehaviors> <behavior name="WeatherServiceBehavior"> <serviceMetadata httpGetEnabled="true"/> <serviceDebug includeExceptionDetailInFaults="False"/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> </configuration> Thanks Lijo

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• php, mySQL & AJAX: Unable to use sessions across the scripts in the same domain

  - by Devner

  Hi all, I have the following pages: page1.php, page2.php and page3.php. Code in each of them is as below CODE: page1.php <script type="text/javascript"> $(function(){ $('#imgID').upload({ submit_to_url: "page2.php", file_name: 'myfile1', description : "Image", limit : 1, file_types : "*.jpg", }) }); </script> <body> <form action="page3.php" method="post" enctype="multipart/form-data" name="frm1" id="frm1"> //Some other text fields <input type="submit" name="submit" id="submit" value="Submit" /> </form> </body> page2.php <?php session_start(); $a = $_SESSION['a']; $b = $_SESSION['b']; $c = $_SESSION['c']; $res = mysql_query("SELECT col FROM table WHERE col1 = $a AND col2 = $b AND col3 = $c LIMIT 1"); $num_rows = mysql_num_rows($res); echo $num_rows; //echos 0 when in fact it should have been 1 because the data in the Session exists. //Ok let's proceed further //... Do some stuff... //Store some more values and create new session variables (and assume that page1.php is going to be able to use it) $_SESSION['d'] = 'd'; $_SESSION['e'] = 'e'; $_SESSION['f'] = 'f'; if (move_uploaded_file($_FILES['file']['tmp_name'], $file)) { echo "success"; } else { echo "error ".$_FILES['file']['error']; } ?> page3.php <?php session_start(); if( isset($_POST['submit']) ) { //These sessions are non-existent although the AJAX request //to page2.php may have created them when called via AJAX from within page1.php echo $_SESSION['d'].$_SESSION['e'].$_SESSION['f']; ?> } ?> As the code says it I am posting some info via AJAX call from page1.php to page2.php. page2.php is supposed to be able to use the session values from page1.php i.e. $_SESSION['a'], $_SESSION['b'] and $_SESSION['c'] but it does not. Why? How can I fix this? page2.php is creating some more sessions after some processing is done and a response is sent back to page1.php. The submit button of the form on page1.php is hit and the page gets POST'ed to page3.php. But when the SESSION info that gets created in page2.php is echoed, it's blank signifying that SESSIONS from page2.php are not used. How can I fix this? I looked over a lot of information and have spent about 50 hours trying to do different things with my scripts before arriving at the above conclusions. My app. is custom made using function (not OOPS) and does not use any PHP frameworks & I am not even about to use any as my knowledge of OOP concepts is limited any many frameworks are object oriented. I came across race conditions, but the solutions provided don't help too much. One more solution of using DB to hold sessions and seek and retrieve from DB is the last thing on my mind and I really want to avoid creating table, coding and maintaining code for a task as simple as just keeping sessions across pages in the same domain. So my request is: Is there a way that I can solve the above problem(s) via simple coding in present conditions? Any help is appreciated. Thank you.

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• "Attach or Add an entity that is not new...loaded from another DataContext. This is not supported."

  - by sah302

  Similar error as other questions, but not quite the same, I am not trying to attach anything. What I am trying to do is insert a new row into a linking table, specifically UserAccomplishment. Relations are set in LINQ to User and Accomplishment Tables. I have a generic insert function: Public Function insertRow(ByVal entity As ImplementationType) As Boolean If entity IsNot Nothing Then Dim lcfdatacontext As New LCFDataContext() Try lcfdatacontext.GetTable(Of ImplementationType)().InsertOnSubmit(entity) lcfdatacontext.SubmitChanges() lcfdatacontext.Dispose() Return True Catch ex As Exception Return False End Try Else Return False End If End Function If you try and give UserAccomplishment the two appropriate objects this will naturally crap out if either the User or Accomplishment already exist. It only works when both user and accomplishment don't exist. I expected this behavior. What does work is simply giving the userAccomplishment object a user.id and accomplishment.id and populating the rest of the fields. This works but is kind of awkward to use in my app, it would be much easier to simply pass in both objects and have it work out what already exists and what doesn't. Okay so I made the following (please ignore the fact that this is horribly inefficient because I know it is): Public Class UserAccomplishmentDao Inherits EntityDao(Of UserAccomplishment) Public Function insertLinkerObjectRow(ByVal userAccomplishment As UserAccomplishment) Dim insertSuccess As Boolean = False If Not userAccomplishment Is Nothing Then Dim userDao As New UserDao() Dim accomplishmentDao As New AccomplishmentDao() Dim user As New User() Dim accomplishment As New Accomplishment() 'see if either object already exists in db' user = userDao.getOneByValueOfProperty("Id", userAccomplishment.User.Id) accomplishment = accomplishmentDao.getOneByValueOfProperty("Id", userAccomplishment.Accomplishment.Id) If user Is Nothing And accomplishment Is Nothing Then 'neither the user or the accomplishment exist, both are new so insert them both, typical insert' insertSuccess = Me.insertRow(userAccomplishment) ElseIf user Is Nothing And Not accomplishment Is Nothing Then 'user is new, accomplishment is not new, so just insert the user, and the relation in userAccomplishment' Dim userWithExistingAccomplishment As New UserAccomplishment(userAccomplishment.User, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userWithExistingAccomplishment) ElseIf Not user Is Nothing And accomplishment Is Nothing Then 'user is not new, accomplishment is new, so just insert the accomplishment, and the relation in userAccomplishment' Dim existingUserWithAccomplishment As New UserAccomplishment(userAccomplishment.UserId, userAccomplishment.Accomplishment, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(existingUserWithAccomplishment) Else 'both are not new, just add the relation' Dim userAccomplishmentBothExist As New UserAccomplishment(userAccomplishment.User.Id, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userAccomplishmentBothExist) End If End If Return insertSuccess End Function End Class Alright, here I basically check if the supplied user and accomplishment already exists in the db, and if so call an appropriate constructor that will leave whatever already exists empty, but supply the rest of the information so the insert can succeed. However, upon trying an insert: Dim result As Boolean = Me.userAccomplishmentDao.insertLinkerObjectRow(userAccomplishment) In which the user already exists, but the accomplishment does not (the 99% typical scenario) I get the error: "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." I have debugged this multiple times now and am not sure why this is occuring, if either User or Accomplishment exist, I am not including it in the final object to try to insert. So nothing appears to be attempted to be added. Even in debug, upon insert, the object was set to empty. So the accomplishment is new and the user is empty. 1) Why is it still saying that and how can I fix it ..using my current structure 2) Pre-emptive 'use repository pattern answers' - I know this way kind of sucks in general and I should be using the repository pattern. However, I can't use that in the current project because I don't have time to refactor that due to my non existence knowledge of it and time constraints. The usage of the app is going to so small that the inefficient use of datacontext's and what have you won't matter so much. I can refactor it once it's up and running, but for now I just need to 'push through' with my current structure. Edit: I also just tested this when having both already exists, and only insert each object's IDs into the table, that works. So I guess I could manually insert whichever object doesn't exist as a single insert, then put the ids only into the linking table, but I still don't know why when one object exists, and I make it empty, it doens't work.

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• RackSpace Cloud Strips $_SESSION if URL Has Certain File Extensions

  - by macinjosh

  The Situation I am creating a video training site for a client on the RackSpace Cloud using the traditional LAMP stack (RackSpace's cloud has both Windows and LAMP stacks). The videos and other media files I'm serving on this site need to be protected as my client charges money for access to them. There is no DRM or funny business like that, essentially we store the files outside of the web root and use PHP to authenticate user's before they are able to access the files by using mod_rewrite to run the request through PHP. So let's say the user requests a file at this URL: http://www.example.com/uploads/preview_image/29.jpg I am using mod_rewrite to rewrite that url to: http://www.example.com/files.php?path=%2Fuploads%2Fpreview_image%2F29.jpg Here is a simplified version of the files.php script: <?php // Setups the environment and sets $logged_in // This part requires $_SESSION require_once('../../includes/user_config.php'); if (!$logged_in) { // Redirect non-authenticated users header('Location: login.php'); } // This user is authenticated, continue $content_type = "image/jpeg"; // getAbsolutePathForRequestedResource() takes // a Query Parameter called path and uses DB // lookups and some string manipulation to get // an absolute path. This part doesn't have // any bearing on the problem at hand $file_path = getAbsolutePathForRequestedResource($_GET['path']); // At this point $file_path looks something like // this: "/path/to/a/place/outside/the/webroot" if (file_exists($file_path) && !is_dir($file_path)) { header("Content-Type: $content_type"); header('Content-Length: ' . filesize($file_path)); echo file_get_contents($file_path); } else { header('HTTP/1.0 404 Not Found'); header('Status: 404 Not Found'); echo '404 Not Found'; } exit(); ?> The Problem Let me start by saying this works perfectly for me. On local test machines it works like a charm. However once deployed to the cloud it stops working. After some debugging it turns out that if a request to the cloud has certain file extensions like .JPG, .PNG, or .SWF (i.e. extensions of typically static media files.) the request is routed to a cache system called Varnish. The end result of this routing is that by the time this whole process makes it to my PHP script the session is not present. If I change the extension in the URL to .PHP or if I even add a query parameter Varnish is bypassed and the PHP script can get the session. No problem right? I'll just add a meaningless query parameter to my requests! Here is the rub: The media files I am serving through this system are being requested through compiled SWF files that I have zero control over. They are generated by third-party software and I have no hope of adding or changing the URLs that they request. Are there any other options I have on this? Update: I should note that I have verified this behavior with RackSpace support and they have said there is nothing they can do about it.

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• multipart file-upload post request from java

  - by Martin

  I'm trying to make a program that uploads a image to a webserver that accepts multipart file-uploads. More specificly i want to make a http POST request to http://iqs.me that sends a file in the variable "pic". I've made a lot of tries but i don't know if i've even been close. The hardest part seems to be to get a HttpURLConnection to make a request of the type POST. The response i get looks like it makes a GET. (And i want to do this without any third party libs) UPDATE: non-working code goes here (no errors but doesn't seem to do a POST): HttpURLConnection conn = null; BufferedReader br = null; DataOutputStream dos = null; DataInputStream inStream = null; InputStream is = null; OutputStream os = null; boolean ret = false; String StrMessage = ""; String exsistingFileName = "myScreenShot.png"; String lineEnd = "\r\n"; String twoHyphens = "--"; String boundary = "*****"; int bytesRead, bytesAvailable, bufferSize; byte[] buffer; int maxBufferSize = 1*1024*1024; String responseFromServer = ""; String urlString = "http://iqs.local.com/index.php"; try{ FileInputStream fileInputStream = new FileInputStream( new File(exsistingFileName) ); URL url = new URL(urlString); conn = (HttpURLConnection) url.openConnection(); conn.setDoInput(true); conn.setDoOutput(true); conn.setRequestMethod("POST"); conn.setUseCaches(false); conn.setRequestProperty("Connection", "Keep-Alive"); conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary); dos = new DataOutputStream( conn.getOutputStream() ); dos.writeBytes(twoHyphens + boundary + lineEnd); dos.writeBytes("Content-Disposition: form-data; name=\"pic\";" + " filename=\"" + exsistingFileName +"\"" + lineEnd); dos.writeBytes(lineEnd); bytesAvailable = fileInputStream.available(); bufferSize = Math.min(bytesAvailable, maxBufferSize); buffer = new byte[bufferSize]; bytesRead = fileInputStream.read(buffer, 0, bufferSize); while (bytesRead > 0){ dos.write(buffer, 0, bufferSize); bytesAvailable = fileInputStream.available(); bufferSize = Math.min(bytesAvailable, maxBufferSize); bytesRead = fileInputStream.read(buffer, 0, bufferSize); } dos.writeBytes(lineEnd); dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd); fileInputStream.close(); dos.flush(); dos.close(); }catch (MalformedURLException ex){ System.out.println("Error:"+ex); }catch (IOException ioe){ System.out.println("Error:"+ioe); } try{ inStream = new DataInputStream ( conn.getInputStream() ); String str; while (( str = inStream.readLine()) != null){ System.out.println(str); } inStream.close(); }catch (IOException ioex){ System.out.println("Error: "+ioex); }

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• C++: casting to void* and back

  - by MInner

  * ---Edit - now the whole sourse* When I debug it on the end, "get" and "value" have different values! Probably, I convert to void* and back to User the wrong way? #include <db_cxx.h> #include <stdio.h> struct User{ User(){} int name; int town; User(int a){}; inline int get_index(int a){ return town; } //for another stuff }; int main(){ try { DbEnv* env = new DbEnv(NULL); env->open("./", DB_CREATE | DB_INIT_MPOOL | DB_THREAD | DB_INIT_LOCK | DB_INIT_TXN | DB_RECOVER | DB_INIT_LOG, 0); Db* datab = new Db(env, 0); datab->open(NULL, "db.dbf", NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT, 0); Dbt key, value, get; char a[10] = "bbaaccd"; User u; u.name = 1; u.town = 34; key.set_data(a); key.set_size(strlen(a) + 1 ); value.set_data((void*)&u); value.set_size(sizeof(u)); get.set_flags(DB_DBT_MALLOC); DbTxn* txn; env->txn_begin(NULL, &txn, 0); datab->put(txn, &key, &value, 0); datab->get(txn, &key, &get, 0); txn->commit(0); User g; g = *((User*)&get); printf("%d", g.town); getchar(); return 0; }catch (DbException &e){ printf("%s", e.what()); getchar(); } solution create a kind of "serializator" what would convert all POD's into void* and then will unite these pieces PS Or I'd rewrite User into POD type and everything will be all right, I hope. Add It's strange, but... I cast a defenetly non-pod object to void* and back (it has std::string inside) and it's all right (without sending it to the db and back). How could it be? And after I cast and send 'trough' db defenetly pod object (no extra methods, all members are pod, it's a simple struct {int a; int b; ...}) I get back dirted one. What's wrong with my approach? Add about week after first 'add' Damn... I've compiled it ones, just for have a look at which kind of dirt it returnes, and oh! it's okay!... I can't ! ... AAh!.. Lord... A reasonable question (in 99.999 percent of situations right answer is 'my', but... here...) - whos is this fault? My or VSs?

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• How do I launch a WPF app from command.com. I'm getting a FontCache error.

  - by jttraino

  I know this is not ideal, but my constraint is that I have a legacy application written in Clipper. I want to launch a new, WinForms/WPF application from inside the application (to ease transition). This legacy application written in Clipper launches using: SwpRunCmd("C:\MyApp\MyBat.bat",0) The batch file contains something like this command: C:\PROGRA~1\INTERN~1\iexplore "http://QASVR/MyApp/AppWin/MyCompany.MyApp.AppWin.application#MyCompany.MyApp.AppWin.application" It is launching a WinForms/WPF app that is we deploy via ClickOnce. Everything has been going well until we introduced WPF into the application. We were able to easily launch from the legacy application. Since we have introduced WPF, however, we have the following behavior. If we launch via the Clipper application first, we get an exception when launching the application. The error text is: The type initializer for 'System.Windows.FrameworkElement' threw an exception. at System.Windows.FrameworkElement..ctor() at System.Windows.Controls.Panel..ctor() at System.Windows.Controls.DockPanel..ctor() at System.Windows.Forms.Integration.AvalonAdapter..ctor(ElementHost hostControl) at System.Windows.Forms.Integration.ElementHost..ctor() at MyCompany.MyApp.AppWin.Main.InitializeComponent() at MyCompany.MyApp.AppWin.Main..ctor(String[] args) at MyCompany.MyApp.AppWin.Program.Main(String[] args) The type initializer for 'System.Windows.Documents.TextElement' threw an exception. at System.Windows.FrameworkElement..cctor() The type initializer for 'System.Windows.Media.FontFamily' threw an exception. at System.Windows.Media.FontFamily..ctor(String familyName) at System.Windows.SystemFonts.get_MessageFontFamily() at System.Windows.Documents.TextElement..cctor() The type initializer for 'MS.Internal.FontCache.Util' threw an exception. at MS.Internal.FontCache.Util.get_WindowsFontsUriObject() at System.Windows.Media.FontFamily.PreCreateDefaultFamilyCollection() at System.Windows.Media.FontFamily..cctor() Invalid URI: The format of the URI could not be determined. at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind) at System.Uri..ctor(String uriString, UriKind uriKind) at MS.Internal.FontCache.Util..cctor() If we launch the application via the URL (in IE) or via the icon on the desktop first, we do not get the exception and application launches as expected. The neat thing is that whatever we launch with first determines whether the app will launch at all. So, if we launch with legacy first, it breaks right away and we can't get the app to run even if we launch with the otherwise successful URL or icon. To get it to work, we have to logout and log back in and start it from the URL or icon. If we first use the URL or the icon, we have no problem launching from the legacy application from that point forward (until we logout and come back in). One other piece of information is that we are able to simulate the problem in the following fashion. If we enter a command prompt using "cmd.exe" and execute a statement to launch from a URL, we are successful. If, however, we enter a command prompt using "command.com" and we execute that same statement, we experience the breaking behavior. We assume it is because the legacy application in Clipper uses the equivalent of command.com to create the shell to spawn the other app. We have tried a bunch of hacks like having command.com run cmd.exe or psexec and then executing, but nothing seems to work. We have some ideas for workarounds (like making the app launch on startup so we force the successful launch from a URL, making all subsequent launches successful), but they all are sub-optimal even though we have a great deal of control over our workstations. To reduce the chance that this is related to permissions, we have given the launching account administrative rights (as well as non-administrative rights in case that made a difference). Any ideas would be greatly-appreciate. Like I said, we have some work arounds, but I would love to avoid them. Thanks!

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• ASP.NET MVC 3 embrace dynamic type - CSDN.NET - CSDN Software Development Channel

  - by user559071

  About a decade ago, Microsoft will all bet on the WebForms and static types. With the complete package from scattered to the continuous development, and now almost every page can be viewed as its own procedure. Subsequent years, the industry continued to move in another direction, love is better than separation package, better than the late binding early binding to the idea. This leads to two very interesting questions. The first is the problem of terminology. Consider the original Smalltalk MVC model, view and controller is not only tightly coupled together, and usually in pairs. Most of the framework is that Microsoft, including the classic VB, WinForms, WebForms, WPF and Silverlight, they both use the code behind file to store the controller logic. But said "MVC" usually refers to the view and controller are loosely coupled framework. This is especially true for the Web framework, HTML form submission mechanism allows any views submitted to any of the controller. Since this article was mainly talking about Web technologies, so we need to use the modern definition. The second question is "If you're Microsoft, how to change orbit without causing too much pressure to the developer?" So far, the answer is: new releases each year, until the developers meet up. ASP.NET MVC's first product was released last March. Released in March this year, ASP.NET MVC 2.0. 3.0 RC 2 is currently in phase, expected to be released next March. December 10, Microsoft released ASP.NET MVC 3.0 Release Candidate 2. RC 2 is built on top of Microsoft's commitment to the jQuery: The default project template into jQuery 1.4.4, jQuery Validation 1.7 and jQuery UI. Although people think that Microsoft will focus shifted away from server-side controls to be a joke, but the introduction of Microsoft's jQuery UI is that this is the real thing. For those worried about the scalability of the developers, there are many excellent control can replace the session state. With SessionState property, you can tell the controller session state is read-only, read-write, or can be completely ignored in the. This site is no single server, but if a server needs to access another server session state, then this approach can provide a great help. MVC 3 contains Razor view engine. By default, the engine will be encoded HTML output, so that we can easily output on the screen the text of the original. HTML injection attacks even without the risk of encoded text can not easily prevent the page rendering. For many C # developers in the end do what is most shocking that MVC 3 for the controller and view and embrace the dynamic type. ViewBag property will open a dynamic object, developers can run on top of the object to add attributes. In general, it is used to send the view from the controller non-mode data. Scott Guthrie provides state of the sample contains text (such as the current time) and used to assemble the list box entries. Asked Link: http://www.infoq.com/cn/news/2010/12/ASPNET-MVC-3-RC-2; jsessionid = 3561C3B7957F1FB97848950809AD9483

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• How can I disable 'output escaping' in minidom

  - by William

  I'm trying to build an xml document from scratch using xml.dom.minidom. Everything was going well until I tried to make a text node with a ® (Registered Trademark) symbol in. My objective is for when I finally hit print mydoc.toxml() this particular node will actually contain a ® symbol. First I tried: import xml.dom.minidom as mdom data = '®' which gives the rather obvious error of: File "C:\src\python\HTMLGen\test2.py", line 3 SyntaxError: Non-ASCII character '\xae' in file C:\src\python\HTMLGen\test2.py on line 3, but no encoding declared; see http://www.python.or g/peps/pep-0263.html for details I have of course also tried changing the encoding of my python script to 'utf-8' using the opening line comment method, but this didn't help. So I thought import xml.dom.minidom as mdom data = '&#174;' #Both accepted xml encodings for registered trademark data = '&reg;' text = mdom.Text() text.data = data print data print text.toxml() But because when I print text.toxml(), the ampersands are being escaped, I get this output: &reg; &amp;reg; My question is, does anybody know of a way that I can force the ampersands not to be escaped in the output, so that I can have my special character reference carry through to the XML document? Basically, for this node, I want print text.toxml() to produce output of &reg; or &#174; in a happy and cooperative way! EDIT 1: By the way, if minidom actually doesn't have this capacity, I am perfectly happy using another module that you can recommend which does. EDIT 2: As Hugh suggested, I tried using data = u'®' (while also using data # -*- coding: utf-8 -*- Python source tags). This almost helped in the sense that it actually caused the ® symbol itself to be outputted to my xml. This is actually not the result I am looking for. As you may have guessed by now (and perhaps I should have specified earlier) this xml document happens to be an HTML page, which needs to work in a browser. So having ® in the document ends up causing rubbish in the browser (® to be precise!). I also tried: data = unichr(174) text.data = data.encode('ascii','xmlcharrefreplace') print text.toxml() But of course this lead to the same origional problem where all that happens is the ampersand gets escaped by .toxml(). My ideal scenario would be some way of escaping the ampersand so that the XML printing function won't "escape" it on my behalf for the document (in other words, achieving my original goal of having &reg; or &#174; appear in the document). Seems like soon I'm going to have to resort to regular expressions! EDIT 2a: Or perhaps not. Seems like getting my html meta information correct <META http-equiv="Content-Type" Content="text/html; charset=UTF-8"> could help, but I'm not sure yet how this fits in with the xml structure...

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• C# DotNetNuke Module: GridVIew AutoGenerateEditButton is skipping over a field on update.

  - by AlexMax

  I have a GridView with an automatically generated Edit button. I wanted some customized behavior for the Image column, since I wanted it to be a drop down list of items as opposed to a simple input field, and I also wanted some nice "fallback" in case the value in the database didn't actually exist in the drop down list. With the code I have done so far, I have gotten the behavior I desire out of the Image field. The problem is that when i attempt to update that particular field, I get an error spit out back at me that it can't find a method to update the form with: ObjectDataSource 'objDataSource' could not find a non-generic method 'UpdateDiscovery' that has parameters: ModuleId, Visible, Position, Title, Link, ItemId. That's not good, because I DO have an UpdateDiscovery method. However, between Title and Link, there is supposed to be another param that belongs to the Image field, and it's not being passed. I realize that it's probably the update button doesn't know to pass that field, since it's a TemplateField and not a BoundField, and when I use Bind('image') as the selected value for the drop down list, it seems to update fine...but only as long as the field in the database when I try and edit the row actually exists, otherwise it bombs out and gives me an error about the value not existing in the drop down list. I have the following GridView defined: <asp:GridView ID="grdDiscoverys" runat="server" DataSourceID="objDataSource" EnableModelValidation="True" AutoGenerateColumns="false" AutoGenerateEditButton="true" AutoGenerateDeleteButton="true" DataKeyNames="ItemId" OnRowDataBound="cmdDiscovery_RowDataBound"> <Columns> <asp:BoundField DataField="ItemId" HeaderText="#" ReadOnly="true" /> <asp:BoundField DataField="Visible" HeaderText="Visible" /> <asp:BoundField DataField="Position" HeaderText="Position" /> <asp:TemplateField HeaderText="Image"> <ItemTemplate> <asp:Label ID="lblViewImage" runat="server" /> </ItemTemplate> <EditItemTemplate> <asp:DropDownList ID="ddlEditImage" runat="server" title="Image" DataValueField="Key" DataTextField="Value" /> </EditItemTemplate> </asp:TemplateField> <asp:BoundField DataField="Title" HeaderText="Title" /> <asp:BoundField DataField="Link" HeaderText="Link" /> </Columns> </asp:GridView> The datasource that this is tied to: <asp:ObjectDataSource ID="objDataSource" runat="server" TypeName="MyCompany.Modules.Discovery.DiscoveryController" SelectMethod="GetDiscoverys" UpdateMethod="UpdateDiscovery" DeleteMethod="DeleteDiscovery"> <SelectParameters> <asp:QueryStringParameter Name="ModuleId" QueryStringField="mid" /> </SelectParameters> <UpdateParameters> <asp:QueryStringParameter Name="ModuleId" QueryStringField="mid" /> </UpdateParameters> <DeleteParameters> <asp:QueryStringParameter Name="ModuleId" QueryStringField="mid" /> </DeleteParameters> </asp:ObjectDataSource> The cmdDiscovery_RowDataBound method that gets called when the row's data is bound is the following C# code: protected void cmdDiscovery_RowDataBound(object sender, GridViewRowEventArgs e) { try { if (e.Row.RowIndex >= 0) { int intImage = ((DiscoveryInfo)e.Row.DataItem).Image; if (grdDiscoverys.EditIndex == -1) { // View Label lblViewImage = ((Label)e.Row.FindControl("lblViewImage")); if (GetFileDictionary().ContainsKey(intImage)) { lblViewImage.Text = GetFileDictionary()[intImage]; } else { lblViewImage.Text = "Missing Image"; } } else { // Edit DropDownList ddlEditImage = ((DropDownList)e.Row.FindControl("ddlEditImage")); ddlEditImage.DataSource = GetFileDictionary(); ddlEditImage.DataBind(); if (GetFileDictionary().ContainsKey(intImage)) { ddlEditImage.SelectedValue = intImage.ToString(); } } } } catch (Exception exc) { //Module failed to load Exceptions.ProcessModuleLoadException(this, exc); } } How do I make sure that the Image value in the drop down list is passed to the update function?

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• Are there supposed to be more restrictions on operator->* overloads?

  - by Potatoswatter

  I was perusing section 13.5 after refuting the notion that built-in operators do not participate in overload resolution, and noticed that there is no section on operator->*. It is just a generic binary operator. Its brethren, operator->, operator*, and operator[], are all required to be non-static member functions. This precludes definition of a free function overload to an operator commonly used to obtain a reference from an object. But the uncommon operator->* is left out. In particular, operator[] has many similarities. It is binary (they missed a golden opportunity to make it n-ary), and it accepts some kind of container on the left and some kind of locator on the right. Its special-rules section, 13.5.5, doesn't seem to have any actual effect except to outlaw free functions. (And that restriction even precludes support for commutativity!) So, for example, this is perfectly legal (in C++0x, remove obvious stuff to translate to C++03): #include <utility> #include <iostream> #include <type_traits> using namespace std; template< class F, class S > typename common_type< F,S >::type operator->*( pair<F,S> const &l, bool r ) { return r? l.second : l.first; } template< class T > T & operator->*( pair<T,T> &l, bool r ) { return r? l.second : l.first; } template< class T > T & operator->*( bool l, pair<T,T> &r ) { return l? r.second : r.first; } int main() { auto x = make_pair( 1, 2.3 ); cerr << x->*false << " " << x->*4 << endl; auto y = make_pair( 5, 6 ); y->*(0) = 7; y->*0->*y = 8; // evaluates to 7->*y = y.second cerr << y.first << " " << y.second << endl; } I can certainly imagine myself giving into temp[la]tation. For example, scaled indexes for vector: v->*matrix_width[5] = x; Did the standards committee forget to prevent this, was it considered too ugly to bother, or are there real-world use cases?

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• Fluent Nhibernate - how do i specify table schemas when auto generating tables in SQL CE 4

  - by daffers

  I am using SQL CE as a database for running local and CI integration tests (normally our site runs on normal SQL server). We are using Fluent Nhibernate for our mapping and having it create our schema from our Mapclasses. There are only two classes with a one to many relationship between them. In our real database we use a non dbo schema. The code would not work with this real database at first until i added schema names to the Table() methods. However doing this broke the unit tests with the error... System.Data.SqlServerCe.SqlCeException : There was an error parsing the query. [ Token line number = 1,Token line offset = 26,Token in error = User ] These are the classes and associatad MapClasses (simplified of course) public class AffiliateApplicationRecord { public virtual int Id { get; private set; } public virtual string CompanyName { get; set; } public virtual UserRecord KeyContact { get; private set; } public AffiliateApplicationRecord() { DateReceived = DateTime.Now; } public virtual void AddKeyContact(UserRecord keyContactUser) { keyContactUser.Affilates.Add(this); KeyContact = keyContactUser; } } public class AffiliateApplicationRecordMap : ClassMap<AffiliateApplicationRecord> { public AffiliateApplicationRecordMap() { Schema("myschema"); Table("Partner"); Id(x => x.Id).GeneratedBy.Identity(); Map(x => x.CompanyName, "Name"); References(x => x.KeyContact) .Cascade.All() .LazyLoad(Laziness.False) .Column("UserID"); } } public class UserRecord { public UserRecord() { Affilates = new List<AffiliateApplicationRecord>(); } public virtual int Id { get; private set; } public virtual string Forename { get; set; } public virtual IList<AffiliateApplicationRecord> Affilates { get; set; } } public class UserRecordMap : ClassMap<UserRecord> { public UserRecordMap() { Schema("myschema"); Table("[User]");//Square brackets required as user is a reserved word Id(x => x.Id).GeneratedBy.Identity(); Map(x => x.Forename); HasMany(x => x.Affilates); } } And here is the fluent configuraton i am using .... public static ISessionFactory CreateSessionFactory() { return Fluently.Configure() .Database( MsSqlCeConfiguration.Standard .Dialect<MsSqlCe40Dialect>() .ConnectionString(ConnectionString) .DefaultSchema("myschema")) .Mappings(m => m.FluentMappings.AddFromAssembly(typeof(AffiliateApplicationRecord).Assembly)) .ExposeConfiguration(config => new SchemaExport(config).Create(false, true)) .ExposeConfiguration(x => x.SetProperty("connection.release_mode", "on_close")) //This is included to deal with a SQLCE issue http://stackoverflow.com/questions/2361730/assertionfailure-null-identifier-fluentnh-sqlserverce .BuildSessionFactory(); } The documentation on this aspect of fluent is pretty weak so any help would be appreciated

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• Geolocation through Android's GPS Provider on a website?

  - by Corey Ogburn

  I'm trying to get the geolocation of the mobile device in a regular website, not a webview of an application or anything native like that. I'm getting a location, but it's highly inaccurate, the accuracy comes back as 3230 or some other outrageous number. I'm assuming that's in meters, either way it's not nearly accurate enough. By comparison, the same webpage on a laptop gets an accuracy of 30-40. My first thought was that it was using the Network Provider instead of the GPS Provider, telling me where I am based on tower location and reach. A little research later I found enableHighAccuracy and set it true in the options that I pass. After including that, I still notice no difference. Here's the test page's HTML/javascript: <html> <head> <script type="text/javascript" src="http://ecn.dev.virtualearth.net/mapcontrol/mapcontrol.ashx?v=7.0"></script> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.3/jquery.min.js"></script> <script type="text/javascript"> function OnLoad() { $("#Status").text("Init"); if (navigator.geolocation) { $("#Status").text("Supports Geolocation"); navigator.geolocation.getCurrentPosition(HandleLocation, LocationError, { enableHighAccuracy: true }); $("#Status").text("Sent position request..."); } else { $("#Status").text("Doesn't support geolocation"); } } function HandleLocation(position) { $("#Status").text("Received response:"); $("#Position").text("(" + position.coords.latitude + ", " + position.coords.longitude + ") accuracy: " + position.coords.accuracy); var loc = new Microsoft.Maps.Location(position.coords.latitude, position.coords.longitude); GetMap(loc); } function LocationError(error) { switch(error.code) { case error.PERMISSION_DENIED: alert("Location not provided"); break; case error.POSITION_UNAVAILABLE: alert("Current location not available"); break; case error.TIMEOUT: alert("Timeout"); break; default: alert("unknown error"); break; } } function GetMap(loc) { var map = new Microsoft.Maps.Map(document.getElementById("mapDiv"), {credentials: "Aj59meaCR1e7rNgkfQy7j08Pd3mzfP1r04hGesGmLe2a3ZwZ3iGecwPX2SNPWq5a", center: loc, mapTypeId: Microsoft.Maps.MapTypeId.road, zoom: 15}); } </script> </head> <body onload="javascript:OnLoad()"> <div id="Status"></div> <div id="Position"></div><br/> <div id='mapDiv' style="position:relative; width:600px; height:400px;"></div> </body> </html> I'm testing this on a rooted MyTouch 3G running Cyanogen 6.1 stable, Android 2.2 and GPS is enabled. In case rooting was a problem, I have also had various friends and coworkers try the webpage on their non-rooted 2.0+ Android devices. Each phone had various effects on the accuracy, but none were better than 1000, I attribute this to the different carriers. I have not (but eventually will) tested with iPhone or other location-aware cell phones.

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• How to access Hibernate session from src folder?

  - by firnnauriel

  I would like to know how to access the Service and Domains properly in this sample class placed in src/java folder public class NewsIngestion implements Runnable { private String str; private int num; private Logger log = Logger.getLogger("grails.app"); private static boolean isRunning; private Thread t; private WorkerJobService jobService; private NewsService newsService; public NewsIngestion(String s, int n) { jobService = new WorkerJobService(); newsService = new NewsService(); str = s; num = n; isRunning = false; t = new Thread (this, "NewsIngestion"); } public void run () { while(isRunning){ try{ if(jobService.isJobEnabled("ConsumeFeedsJob") && jobService.lockJob("ConsumeFeedsJob")){ log.info("${this.class.name}: ConsumeFeedsJob started"); try{ // get all sources List sources = (List) InvokerHelper.invokeMethod(RSSFeed.class, "list", null); for(int i = 0; i < sources.size(); i++) { RSSFeed s = (RSSFeed) sources.get(i); // check if it's time to read the source int diff = DateTimeUtil.getSecondsDateDiff(s.getLastChecked(), new Date()); if(s.getLastChecked() == null || diff >= s.getCheckInterval()){ List keyword_list = (List) InvokerHelper.invokeMethod(Keyword.class, "list", null); for(int j = 0; j < keyword_list.size(); j++) { String keyword = (String) keyword_list.get(j); try{ newsService.ingestNewsFromSources(keyword, s); }catch(Exception e){ log.error("${this.class.name}: ${e}"); } log.debug("Completed reading feeds for ${keyword}."); log.info("${this.class.name}: Reading feeds for '${keyword}' (${s.feedName}) took ${Float.toString(st2.getDuration())} second(s)."); } s.setLastChecked(new Date()); InvokerHelper.invokeMethod(RSSFeed.class, "save", null); } log.info("${this.class.name}: Reading feeds for '${s.feedName}' for all keywords took ${Float.toString(st.getDuration())} second(s)."); } }catch(Exception e){ log.error("${this.class.name}: Exception: ${e}"); } log.info("${this.class.name}: ConsumeFeedsJob ended."); // unlock job jobService.unlockJob("ConsumeFeedsJob"); } log.info("alfred: success"); } catch (Exception e){ log.info("alfred exception: " + e.getMessage()); } try { Thread.sleep(5000); } catch (InterruptedException e) { log.info(e.getMessage()); } } } public void start() { if(t == null){ t = new Thread (this, "NewsIngestion"); } if(!isRunning){ isRunning = true; t.start(); } } public void stop() { isRunning = false; } public boolean isRunning() { return isRunning; } } I'm encountering this error message: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here Thanks.

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• gzip compression using varnish cache

  - by Ali Raza

  Im trying to provide gzip compression using varnish cache. But when I set content-encoding as gzip using my below mentioned configuration for varnish (default.vcl). Browser failed to download those content for which i set content-encoding as gzipped. Varnish configuration file: backend default { .host = "127.0.0.1"; .port = "9000"; } backend socketIO { .host = "127.0.0.1"; .port = "8083"; } acl purge { "127.0.0.1"; "192.168.15.0"/24; } sub vcl_fetch { /* If the request is for pictures, javascript, css, etc */ if (req.url ~ "^/public/" || req.url ~ "\.js"){ unset req.http.cookie; set beresp.http.Content-Encoding= "gzip"; set beresp.ttl = 86400s; set beresp.http.Cache-Control = "public, max-age=3600"; /*set the expires time to response header*/ set beresp.http.expires=beresp.ttl; /* marker for vcl_deliver to reset Age: */ set beresp.http.magicmarker = "1"; } if (!beresp.cacheable) { return (pass); } return (deliver); } sub vcl_deliver { if (resp.http.magicmarker) { /* Remove the magic marker */ unset resp.http.magicmarker; /* By definition we have a fresh object */ set resp.http.age = "0"; } if(obj.hits > 0) { set resp.http.X-Varnish-Cache = "HIT"; }else { set resp.http.X-Varnish-Cache = "MISS"; } return (deliver); } sub vcl_recv { if (req.http.x-forwarded-for) { set req.http.X-Forwarded-For = req.http.X-Forwarded-For ", " client.ip; } else { set req.http.X-Forwarded-For = client.ip; } if (req.request != "GET" && req.request != "HEAD" && req.request != "PUT" && req.request != "POST" && req.request != "TRACE" && req.request != "OPTIONS" && req.request != "DELETE") { /* Non-RFC2616 or CONNECT which is weird. */ return (pipe); } # Pass requests that are not GET or HEAD if (req.request != "GET" && req.request != "HEAD") { return(pass); } #pipe websocket connections directly to Node.js if (req.http.Upgrade ~ "(?i)websocket") { set req.backend = socketIO; return (pipe); } # Properly handle different encoding types if (req.http.Accept-Encoding) { if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|js|css)$") { # No point in compressing these remove req.http.Accept-Encoding; } elsif (req.http.Accept-Encoding ~ "gzip") { set req.http.Accept-Encoding = "gzip"; } elsif (req.http.Accept-Encoding ~ "deflate") { set req.http.Accept-Encoding = "deflate"; } else { # unkown algorithm remove req.http.Accept-Encoding; } } # allow PURGE from localhost and 192.168.15... if (req.request == "PURGE") { if (!client.ip ~ purge) { error 405 "Not allowed."; } return (lookup); } return (lookup); } sub vcl_hit { if (req.request == "PURGE") { purge_url(req.url); error 200 "Purged."; } } sub vcl_miss { if (req.request == "PURGE") { purge_url(req.url); error 200 "Purged."; } } sub vcl_pipe { if (req.http.upgrade) { set bereq.http.upgrade = req.http.upgrade; } } Response Header: Cache-Control:public, max-age=3600 Connection:keep-alive Content-Encoding:gzip Content-Length:11520 Content-Type:application/javascript Date:Fri, 06 Apr 2012 04:53:41 GMT ETag:"1330493670000--987570445" Last-Modified:Wed, 29 Feb 2012 05:34:30 GMT Server:Play! Framework;1.2.x-localbuild;dev Via:1.1 varnish X-Varnish:118464579 118464571 X-Varnish-Cache:HIT age:0 expires:86400.000 Any suggestion on how to fix it and how to provide gzip compression using varnish.

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• Where are the function address literals in c++?

  - by academicRobot

  First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). <UPDATE> After some reading with help from answer by Chris Dodd, what I'm looking for is literal function addresses as template parameters. Chris' answer indicates how to do this for standard functions, but how can the addresses of member functions be used as template parameters? Since the standard prohibits non-static member function addresses as template parameters (c++03 14.3.2.3), I suspect the work around is quite complicated. Any ideas for a workaround? Below the original form of the question is left as is for context. </UPDATE> The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one. Edit The intent of this question is not to implement delegates, rather to identify a pattern that will embed a conventional function call, (in immediate mode) directly into third party code, possibly a template.

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• TDD - beginner problems and stumbling blocks

  - by Noufal Ibrahim

  While I've written unit tests for most of the code I've done, I only recently got my hands on a copy of TDD by example by Kent Beck. I have always regretted certain design decisions I made since they prevented the application from being 'testable'. I read through the book and while some of it looks alien, I felt that I could manage it and decided to try it out on my current project which is basically a client/server system where the two pieces communicate via. USB. One on the gadget and the other on the host. The application is in Python. I started off and very soon got entangled in a mess of rewrites and tiny tests which I later figured didn't really test anything. I threw away most of them and and now have a working application for which the tests have all coagulated into just 2. Based on my experiences, I have a few questions which I'd like to ask. I gained some information from http://stackoverflow.com/questions/1146218/new-to-tdd-are-there-sample-applications-with-tests-to-show-how-to-do-tdd but have some specific questions which I'd like answers to/discussion on. Kent Beck uses a list which he adds to and strikes out from to guide the development process. How do you make such a list? I initially had a few items like "server should start up", "server should abort if channel is not available" etc. but they got mixed and finally now, it's just something like "client should be able to connect to server" (which subsumed server startup etc.). How do you handle rewrites? I initially selected a half duplex system based on named pipes so that I could develop the application logic on my own machine and then later add the USB communication part. It them moved to become a socket based thing and then moved from using raw sockets to using the Python SocketServer module. Each time things changed, I found that I had to rewrite considerable parts of the tests which was annoying. I'd figured that the tests would be a somewhat invariable guide during my development. They just felt like more code to handle. I needed a client and a server to communicate through the channel to test either side. I could mock one of the sides to test the other but then the whole channel wouldn't be tested and I worry that I'd miss that. This detracted from the whole red/green/refactor rhythm. Is this just lack of experience or am I doing something wrong? The "Fake it till you make it" left me with a lot of messy code that I later spent a lot of time to refactor and clean up. Is this the way things work? At the end of the session, I now have my client and server running with around 3 or 4 unit tests. It took me around a week to do it. I think I could have done it in a day if I were using the unit tests after code way. I fail to see the gain. I'm looking for comments and advice from people who have implemented large non trivial projects completely (or almost completely) using this methodology. It makes sense to me to follow the way after I have something already running and want to add a new feature but doing it from scratch seems to tiresome and not worth the effort. P.S. : Please let me know if this should be community wiki and I'll mark it like that. Update 0 : All the answers were equally helpful. I picked the one I did because it resonated with my experiences the most. Update 1: Practice Practice Practice!

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• Why does my performance slow to a crawl I move methods into a base class?

  - by Juliet

  I'm writing different implementations of immutable binary trees in C#, and I wanted my trees to inherit some common methods from a base class. However, I find. I have lots of binary tree data structures to implement, and I wanted move some common methods into in a base binary tree class. Unfortunately, classes which derive from the base class are abysmally slow. Non-derived classes perform adequately. Here are two nearly identical implementations of an AVL tree to demonstrate: AvlTree: http://pastebin.com/V4WWUAyT DerivedAvlTree: http://pastebin.com/PussQDmN The two trees have the exact same code, but I've moved the DerivedAvlTree.Insert method in base class. Here's a test app: using System; using System.Collections.Generic; using System.Diagnostics; using System.Linq; using Juliet.Collections.Immutable; namespace ConsoleApplication1 { class Program { const int VALUE_COUNT = 5000; static void Main(string[] args) { var avlTreeTimes = TimeIt(TestAvlTree); var derivedAvlTreeTimes = TimeIt(TestDerivedAvlTree); Console.WriteLine("avlTreeTimes: {0}, derivedAvlTreeTimes: {1}", avlTreeTimes, derivedAvlTreeTimes); } static double TimeIt(Func<int, int> f) { var seeds = new int[] { 314159265, 271828183, 231406926, 141421356, 161803399, 266514414, 15485867, 122949829, 198491329, 42 }; var times = new List<double>(); foreach (int seed in seeds) { var sw = Stopwatch.StartNew(); f(seed); sw.Stop(); times.Add(sw.Elapsed.TotalMilliseconds); } // throwing away top and bottom results times.Sort(); times.RemoveAt(0); times.RemoveAt(times.Count - 1); return times.Average(); } static int TestAvlTree(int seed) { var rnd = new System.Random(seed); var avlTree = AvlTree<double>.Create((x, y) => x.CompareTo(y)); for (int i = 0; i < VALUE_COUNT; i++) { avlTree = avlTree.Insert(rnd.NextDouble()); } return avlTree.Count; } static int TestDerivedAvlTree(int seed) { var rnd = new System.Random(seed); var avlTree2 = DerivedAvlTree<double>.Create((x, y) => x.CompareTo(y)); for (int i = 0; i < VALUE_COUNT; i++) { avlTree2 = avlTree2.Insert(rnd.NextDouble()); } return avlTree2.Count; } } } AvlTree: inserts 5000 items in 121 ms DerivedAvlTree: inserts 5000 items in 2182 ms My profiler indicates that the program spends an inordinate amount of time in BaseBinaryTree.Insert. Anyone whose interested can see the EQATEC log file I've created with the code above (you'll need EQATEC profiler to make sense of file). I really want to use a common base class for all of my binary trees, but I can't do that if performance will suffer. What causes my DerivedAvlTree to perform so badly, and what can I do to fix it?

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