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  • How do the size standard libraries compare for different languages

    - by Roman A. Taycher
    Someone was recently raving about how great jQuery was and how it made javascript into a pleasure and also how the whole source code was so small(and one file). I looked it up on www.ohloh.net/ and it said it was about 30,000 lines of javascript, when I tired curl piped to wc it said about 5000 lines(strange discrepancy that, maybe test suites, ect?). I thought well it isn't that strange since javascript from what I've heard has a lot of fun dynamic tricks, so you can probably get away with a small library. But then I thought what about other high level languages, the ones with large standard libraries and wondered how big the standard are for python/ruby/haskell/pharo(smalltalk)/*ml/ect. (libraries not vm stuff to the degree its possible to separate it) Anybody know? Any details (comment/blank/code lines , test code lines, lines in language vs lines in ffi/byte-code) are appreciated! edit: ps. since it started this me asking about jQuery as a bonus if you could please list the size of mega frameworks, a megaframewok provides so much that people using an x megaframework in language y might sometimes refer to programming in xy or even x rather then in y (ie. : qt, jQuery, etc.).

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  • File Storage for Web Applications: Filesystem vs DB vs NoSQL engines

    - by El Yobo
    I have a web application that stores a lot of user generated files. Currently these are all stored on the server filesystem, which has several downsides for me. When we move "folders" (as defined by our application) we also have to move the files on disk (although this is more due to strange design decisions on the part of the original developers than a requirement of storing things on the filesystem). It's hard to write tests for file system actions; I have a mock filesystem class that logs actions like move, delete etc, without performing them, which more or less does the job, but I don't have 100% confidence in the tests. I will be adding some other jobs which need to access the files from other service to perform additional tasks (e.g. indexing in Solr, generating thumbnails, movie format conversion), so I need to get at the files remotely. Doing this over network shares seems dodgy... Dealing with permissions on the filesystem as sometimes given us problems in the past, although now that we've moved to a pure Linux environment this should be less of an issue. What are the downsides of storing files as BLOBs in MySQL? I guess that it would massively increase the database size and reduce the effectiveness of caches, but are there other problems? Do the same problems exist with NoSQL systems like Cassandra? Does anyone have any other suggestions that might be appropriate?

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  • VB.NET switching from ADO.NET to LINQ

    - by Cj Anderson
    I'm VERY new to Linq. I have an application I wrote that is in VB.NET 2.0. Works great, but I'd like to switch this application to Linq. I use ADO.NET to load XML into a datatable. The XML file has about 90,000 records in it. I then use the Datatable.Select to perform searches against that Datatable. The search control is a free form textbox. So if the user types in terms it searches instantly. Any further terms that are typed in continue to restrict the results. So you can type in Bob, or type in Bob Barker. Or type in Bob Barker Price is Right. The more criteria typed in the more narrowed your result. I bind the results to a gridview. Moving forward what all do I need to do? From a high level, I assume I need to: 1) Go to Project Properties -- Advanced Compiler Settings and change the Target framework to 3.5 from 2.0. 2) Add the reference to System.XML.Linq, Add the Imports statement to the classes. So I'm not sure what the best approach is going forward after that. I assume I use XDocument.Load, then my search subroutine runs against the XDocument. Do I just do the standard Linq query for this sort of repeated search? Like so: var people = from phonebook in doc.Root.Elements("phonebook") where phonebook.Element("userid") = "whatever" select phonebook; Any tips on how to best implement?

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  • Download Current WSJ.com Prime Rate

    - by Registered User
    I need to automatically download the current Wall Street Journal Prime Rate and load the data into my database. What is the best method for downloading this data automatically? I have come up with three possible solutions for doing this: Scrape a HTML web page from WSJ. Parse a RSS news feed from WSJ. Use some API that I haven't found from WSJ. Regarding solution 1, although I don't like solution 1 since it could easily break, it's the only one that I have worked out from end to end. It appears I can scrape this page with a WebRequest / WebResponse and read the text in this code: <tr> <td style="text-align:left" class="colhead">&nbsp;</td> <td class="colhead">Latest</td> <td class="colhead">Wk ago</td> <td class="colhead">High</td> <td class="colhead">Low</td> </tr> <tr> <td class="text">U.S.</td> <td style="font-weight:bold;" class="num">3.25</td> <td class="num">3.25</td> <td class="num">3.25</td> <td class="num" style="border-right:0px">3.25</td> </tr> Regarding solution 2, although I can implement a RSS reader solution, I don't see a way to reliably anticipate verbiage for changes in the Prime Rate. Therefore, I don't think this is as safe or reliable a way to get the data as solution 1. Regarding solution 3, I haven't found any published API's for checking money rates like the Prime Rate. If anyone knows of a web service or other API for checking money rates, then please let me know.

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  • Python: Beginning problems

    - by Blogger
    ok so basically i very new to programming and have no idea how to go about these problems help if you will ^^ Numerologists claim to be able to determine a person’s character traits based on the “numeric value” of a name. The value of a name is determined by summing up the values of the letters of the name, where ‘a’ is 1, ‘b’ is 2, ‘c’ is 3 etc., up to ‘z’ being 26. For example, the name “Zelle” would have the value 26 + 5 + 12 + 12 + 5 = 60 (which happens to be a very suspicious number, by the way). Write a program that calculates the numeric value of a single name provided as input. Word count. A common utility on Unix/Linux systems is a small program called “wc”. This program counts the number of lines, words (strings of characters separated by blanks, tabs, or new lines), and characters in a file. Write your own version of this program. The program should accept a file name as input and then print three numbers showing the count of lines, words, and characters in the file.

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  • How do tools like Hiphop for PHP deal with heterogenous arrays?

    - by Derek Thurn
    I think HipHop for PHP is an interesting tool. It essentially converts PHP code into C++ code. Cross compiling in this manner seems like a great idea, but I have to wonder, how do they overcome the fundamental differences between the two type systems? One specific example of my general question is heterogeneous data structures. Statically typed languages don't tend to let you put arbitrary types into an array or other container because they need to be able to figure out the types on the other end. If I have a PHP array like this: $mixedBag = array("cat", 42, 8.5, false); How can this be represented in C++ code? One option would be to use void pointers (or the superior version, boost::any), but then you need to cast when you take stuff back out of the array... and I'm not at all convinced that the type inferencer can always figure out what to cast to at the other end. A better option, perhaps, would be something more like a union (or boost::variant), but then you need to enumerate all possible types at compile time... maybe possible, but certainly messy since arrays can contain arbitrarily complex entities. Does anyone know how HipHop and similar tools which go from a dynamic typing discipline to a static discipline handle these types of problems?

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  • How can I visualise a "broken" hierarchical dataset?

    I have a reasonably large datatable structured something like this: StaffNo Grade Direct Boss2 Boss3 Boss4 Boss5 Boss6 ------- ----- ----- ----- ----- ----- ----- ----- 10001 1 10002 10002 10057 10094 10043 10099 10002 2 10057 NULL 10057 10094 10043 10099 10003 1 10004 10004 10057 10094 10043 10099 10004 2 10057 NULL 10057 10094 10043 10099 10057 3 10094 NULL NULL 10094 10043 10099 etc.... i.e. a unique id , their level (grade) in the hierarchy, a record of their bosses ID and the IDs of the supervisors above. (The 2,3,4, etc refers to the boss at that particular grade). The system relies on a strict hierarchy - if you are my boss (/parent) then your boss must be my grandparent. Unfortunately this rule is not enforced within the data model and the data ultimately comes from other systems which don't even know about the rule, let alone observe it. So you and I may share the same boss, but our bosses boss won't be the same. note: I cannot change the data model I cannot fix the data at source. So (for the moment) I have to fix the data once it's in place. Once a fortnight someone will do something which breaks the model and I'll need to modify the procs slightly to resolve. Not ideal, but I'm stuck with this for the next six months. Anyway, specific queries are easy to produce but I find it hard to keep track of the bigger picutre. The application which sits on this runs without complaint regardless but navigating around the system becoming extraordinarily confusing. So my question is: Can anyone recommend a tool (or technique) for generating some kind of "broken tree" diagram in this sort of circumstances? I don't want something that will fix things for me, or attempt statistical analysis but at least something that will give a visual indication of how broken it is at any one time. Note : At the moment this is in a SQL Server database but I'm open to ideas utilising C#, Perl or Python.

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  • One config file for multiple environments

    - by ho
    I'm currently working with systems that has quite a lot of configuration settings that are environment specific (Dev, UAT, Production). Does anyone have any suggestions for minimizing the changes needed to the config file when moving between environments as well as minimizing the duplication of data in the config file? It's mostly Application settings rather than User settings. The way I'm doing it at the moment is something similar to this: <DevConnectionString>xyz</DevConnectionString> <DevInboundPath>xyz</DevInboundPath> <DevProcessedPath>xyz</DevProcessedPath> <UatConnectionString>xyz</UatConnectionString> <UatInboundPath>xyz</UatInboundPath> <UatProcessedPath>xyz</UatProcessedPath> ... <Environment>Dev</Environment> And then I have a class that reads in the Environment setting via the My.Settings class (it's VB project) and then uses that to decide what other settings to retrieve. This leads to too much duplication though so I'm not sure if it's worth it.

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  • Any info about book "Unix Internals: The New Frontiers" by Uresh Vahalia 2nd edition (Jan 2010)

    - by claws
    This summer I'm getting into UNIX (mostly *BSD) development. I've graduate level knowledge about operating systems. I can also understand the code & read from here and there but the thing is I want to make most of my time. Reading books are best for this. From my search I found that these two books The Design and Implementation of the 4.4 BSD Operating System "Unix Internals: The New Frontiers" by Uresh Vahalia are like established books on UNIX OS internals. But the thing is these books are pretty much outdated. yay!! Lucky me. "Unix Internals: The New Frontiers" by Uresh Vahalia 2 edition (Jan 2010) is released. I've been search for information on this book. Sadly, Amazon says "Out of Print--Limited Availability" & I couldn't find any info regarding this book. This is the information I'm looking for: Table of Contents Whats new in this edition? Where the hell can I buy soft-copy of this book? I really cannot afford buying a hardcopy. How can I contact the author? I've lot of hopes & expectations on this book. I've been waiting for its release for a long time. I've sent random mails to & & requesting to have a proper website for this book. I even contacted publisher for any further information but no replies from any one. If you have any other books that you think will help me. I again repeat, I want to get max possible out of these 2.5 months summer.

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  • SQL Server Database In Single User Mode after Failover

    - by jlichauc
    Here is a weird situation we experienced with a SQL Server 2008 Database Mirroring Failover. We have a pair of mirrored databases running in high-availability mode and both the principal and mirror showed as synchronized. As part of some maintenance I triggered a manual failover of the principal to the mirror. However after the failover the principal was now in single-user mode instead of the expected "Principal/Synchronized" state we usually get. The database had been in multi-user mode on the previous principal before this had happened. We ended up stopping all applications, restarting the SQL Server instances, and executing "ALTER DATABASE ... SET MULTI_USER" to bring the database back to the expected "Principal/Synchronized" state in a multi-user mode. Question. Does anyone know where SQL Server stores information about whether a database should be in single-user mode or not? I'm wondering if there is some system database or table that has this setting recorded somewhere. In particular we had an incident once with the database on the original principal (the one I was failing over to) where when trying to detach the database it was put into single-user mode. I'm wondering if that setting is cached somewhere and is the reason that SQL Server put it back into single-user mode after a failover.

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  • Creating Mobile Cross-Platform Scripting Solution

    - by Aplomb
    I am having the dream to design a Mobile cross-platform scripting solution to achieve Developer only need to code once by scripting language(it's possible be Javascript or others need further investigation), then the solution will be able to generate the installation files for multiple mobile platforms like J2me, Android, Symbian, BlackBerry, Palm, Windows Mobile/Phone, iPhone, etc. Using the scripting language, developer can code with unified platform API. And other extension frameworks under scripting language, like, 1. 2D UI framework Most probably using for Mobile Applications, the UI style will compete with native UI framework and no longer every application in particular platform looks similar. 2. 3D UI framework Provide the platforms who has 3D capability can represent their Mobile Application with more fashion 3D style which will be much more abstractive. 3. Variable game engine Developers can can use it for easily and high-quality build games. 4. etc This Mobile solution is providing three points, 1. Cross-Platform 2. Scripting 3. Middleware So guys, what do you think about this idea, is it good for Developers? is it profitable? where is the better direction for this idea?

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  • php simplexmlelement - I can access most properties (except the one with a dash?)

    - by Matthew Steiner
    So I run some code like this: $quote = simplexml_load_string($xml); $quote = $quote->Stock; echo 'Name: '; echo $quote->Name; echo '<br>'; echo 'Sybmol: '; echo $quote->Symbol; echo '<br>'; echo 'Last Price: '; echo $quote->Last; echo '<br>'; echo 'Earnings To Price Ratio: '; echo $quote->P-E; echo '<br>'; I know that the second to last line ($quote-P-E) is incorrect - I don't think you can use dashes like that. But for some reason I can't figure out how to access that property. The weird thing is that's how it's written if I var_dump($quote) (It's towards the end): object(SimpleXMLElement)#17 (16) { ["Symbol"]=> string(4) "AAPL" ["Last"]=> string(6) "271.87" ["Date"]=> string(9) "6/17/2010" ["Time"]=> string(6) "3:59pm" ["Change"]=> string(5) "+4.62" ["Open"]=> string(6) "270.72" ["High"]=> string(6) "272.90" ["Low"]=> string(6) "269.50" ["Volume"]=> string(8) "31195032" ["MktCap"]=> string(6) "247.4B" ["PreviousClose"]=> string(6) "267.25" ["PercentageChange"]=> string(6) "+1.73%" ["AnnRange"]=> string(15) "132.88 - 272.90" ["Earns"]=> string(6) "11.796" ["P-E"]=> string(5) "22.66" ["Name"]=> string(10) "Apple Inc." } How should I be accessing this attribute/property?

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  • Is Git ready to be recommended to my boss?

    - by Mike Weller
    I want to recomment Git to my boss as a new source control system, since we're stuck in the 90s with VSS (ouch), but are the tools and 3rd party support good enough yet? Specifically I'm talking about GUI front-ends similar to TortoiseSVN, decent visual diff/merge support, as well as stuff like email commit notifications and general support from 3rd parties like IDEs and build systems. Even though this will be used by programmers, we really need this kind of stuff in our team. I don't want to leave everyone stuck with a new tool, and even a new source control paradigm (distributed), with nothing but a command-line app and some online tutorials. This would be a step backwards. So what do you think... is Git ready? What decent tools exist for Git and what third party development apps support it? EDIT: My original question was pretty vague so I'm updating it to specifically ask for a list of available tools and 3rd party support for Git. Maybe we can get a community wiki post with a list of stuff. I also do not consider 'use subversion' to be an adequate answer. There are other reasons to use a distributed source control system other than offline editing - private and cheap branches being one of them.

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  • JBoss deployment throws 'java.util.zip.ZipException: error in opening zip file' on Linux?

    - by Kaushalya
    I thought of posting both the question and the answer for others' knowledge. I deployed a large EAR (contained more than ~1024 jars/wars) on JBoss running with Java 6 on Linux, and the deployment process cried throwing the following exception: java.lang.RuntimeException: java.util.zip.ZipException: error in opening zip file) at org.jboss.deployment.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:53) at org.jboss.deployment.MainDeployer.init(MainDeployer.java:901) at org.jboss.deployment.MainDeployer.init(MainDeployer.java:895) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:809) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782) .... Caused by: java.lang.RuntimeException: java.util.zip.ZipException: error in opening zip file at org.jboss.util.file.JarArchiveBrowser.<init>(JarArchiveBrowser.java:74) at org.jboss.util.file.FileProtocolArchiveBrowserFactory.create(FileProtocolArchiveBrowserFactory.java:48) at org.jboss.util.file.ArchiveBrowser.getBrowser(ArchiveBrowser.java:57) at org.jboss.ejb3.EJB3Deployer.hasEjbAnnotation(EJB3Deployer.java:213) .... This was caused by the 'limit of number of open file descriptors' of Linux/Unix operating systems. The default is 1024. You can check the default value using: ulimit -n To increase the number of open file descriptors (say to 2048): ulimit -n 2048 Check the man page of ulimit for more details.

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  • Thoughts on GoGrid vs EC2

    - by Jason
    I am currently hosting my SaaS application at GoGrid (Microsoft stack). Here's what I have: Database Server - physical box, 12 GB RAM, 2 X Quad Core CPU (2.13 GHz Xeon E5506) 2 Web / App servers - cloud servers, 2 GB RAM, 2 VCPUs 300 GB monthly bandwidth I am paying around $900 / month for this. My web / app servers are busting at the seams and need to be upgraded to 4 GB of RAM. I also need a firewall, and GoGrid just added this service for an additional $200. After the upgrade, I will be paying around $1,400. I started looking at Amazon EC2, specifically this config: Database server - "High Memory Double Extra Large Instance" - 34 GB RAM, 13 EC2 compute units 2 Web / App servers - "Large Instance" - 7.5 GB RAM, 4 EC2 compute units If I go with 1 year reserved instances, my upfront cost would be $4,500 and my monthly would be $700. This comes to $1,075 / month when amortized. Amazon also includes a firewall for free. Here are my questions: Do any of you have experience running a database (especially SQL Server) on an EC2 instance? How did it perform compared to a dedicated machine? One of my major concerns is with disk I/O. Amazon's description of a compute unit is fairly vague. Any ideas on how the CPU performance on the database servers would compare? I am hoping that the Amazon solution will provide significantly better performance than my current or even improved GoGrid setup. Having a virtual database server would also be nice in terms of availability. Right now I would be in serious trouble if I had any hardware issues. Thanks for any insight...

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  • Problem in accessing Windows shared folder on Ubuntu using terminal

    - by vikramtheone
    Hi Guys, Description I have 2 systems with me, one running on Windows(Host) and one on Ubuntu, both on a LAN. On the Windows(Host) I develop software intended for the Linux system and because the Linux system has little external memory, my idea to overcome this is by making the project folder on the Host side a Shared Folder with full access and access it on Ubuntu over the network. To achieve this, I have installed Samba on Ubuntu, when I go to Places -> Network I can see the shared project folder and I simply mount it. A link appears on the desktop. Next, using Nautilus I open the link and I can access the contents of the shared folder. Problem Even though I mount the shared project folder, I don't see it appearing in the /media or the /mnt folder, as a result of this I don't know what path to use to access this folder, from the terminal. For example: When, I mounted my USB stick, as expected, a link for the device appears on the Desktop and I also see a folder in the media folder. So, similarly, a mounted shared folder should have appeared on the /mnt folder, too. Can anyone suggest what I should do now? There are many posts around, but no solid solution for this problem. Help!!! :) Vikram

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  • Sharing storage between servers

    - by El Yobo
    I have a PHP based web application which is currently only using one webserver but will shortly be scaling up to another. In most regards this is pretty straightforward, but the application also stores a lot of files on the filesystem. It seems that there are many approaches to sharing the files between the two servers, from the very simple to the reasonably complex. These are the options that I'm aware of Simple network storage NFS SMB/CIFS Clustered filesystems Lustre GFS/GFS2 GlusterFS Hadoop DFS MogileFS What I want is for a file uploaded via one webserver be immediately available if accessed through the other. The data is extremely important and absolutely cannot be lost, so whatever is implemented needs to a) never lose data and b) have very high availability (as good as, or better, than a local filesystem). It seems like the clustered filesystems will also provide faster data access than local storage (for large files) but that isn't of vita importance at the moment. What would you recommend? Do you have any suggestions to add or anything specifically to look out for with the above options? Any suggestions on how to manage backup of data on the clustered filesystems?

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  • Ajax heavy JS apps using excessive amounts of memory over time.

    - by Shane Reustle
    I seem to have some pretty large memory leaks in an app that I am working on. The app itself is not very complex. Every 15 seconds, the page requests approx 40kb of JSON from the server, and draws a table on the page using it. It is cheaper to draw the table over because the data is usually always new. I am attaching a few events to the table, approx 5 per line, 30 lines in the table. I used jQuery's .html() method to put the new html into the container and overwrite the existing. I do this specifically so that jQuery's special cleanup functions go in and attempt to detach all events on the elements in the element that it is overwriting. I then also delete the large variables of html once they are sent to the DOM using delete my_var. I have checked for circular references and attached events that are never cleared a few times, but never REALLY dug into it. I was wondering if someone could give me a few pointers on how to optimize a very heavy app like this. I just picked up "High Performance Javascript" by Nicholas Zakas, but didn't have much time to get into it yet. To give an idea on how much memory this is using, after 4~ hours, it is using about 420,000k on chrome, and much more on Firefox or IE. Thanks!

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  • Slow Python HTTP server on localhost

    - by Abiel
    I am experiencing some performance problems when creating a very simple Python HTTP server. The key issue is that performance is varying depending on which client I use to access it, where the server and all clients are being run on the local machine. For instance, a GET request issued from a Python script (urllib2.urlopen('http://localhost/').read()) takes just over a second to complete, which seems slow considering that the server is under no load. Running the GET request from Excel using MSXML2.ServerXMLHTTP also feels slow. However, requesting the data Google Chrome or from RCurl, the curl add-in for R, yields an essentially instantaneous response, which is what I would expect. Adding further to my confusion is that I do not experience any performance problems for any client when I am on my computer at work (the performance problems are on my home computer). Both systems run Python 2.6, although the work computer runs Windows XP instead of 7. Below is my very simple server example, which simply returns 'Hello world' for any get request. from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer class MyHandler(BaseHTTPRequestHandler): def do_GET(self): print("Just received a GET request") self.send_response(200) self.send_header("Content-type", "text/html") self.end_headers() self.wfile.write('Hello world') return def log_request(self, code=None, size=None): print('Request') def log_message(self, format, *args): print('Message') if __name__ == "__main__": try: server = HTTPServer(('localhost', 80), MyHandler) print('Started http server') server.serve_forever() except KeyboardInterrupt: print('^C received, shutting down server') server.socket.close() Note that in MyHandler I override the log_request() and log_message() functions. The reason is that I read that a fully-qualified domain name lookup performed by one of these functions might be a reason for a slow server. Unfortunately setting them to just print a static message did not solve my problem. Also, notice that I have put in a print() statement as the first line of the do_GET() routine in MyHandler. The slowness occurs prior to this message being printed, meaning that none of the stuff that comes after it is causing a delay.

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  • Redirect uploaded files to another server, using nginx

    - by Serg ikS
    I am creating a web service of scheduled posts to some soc. network.Need help dealing with file uploads under high traffic. Process overview: User uploads files to SomeServer (not mine). SomeServer then responds with a JSON string. My web app should store that JSON response. Opt. 1 — Save, cURL POST, delete tmp The stupid way I made it work: User uploads files to MyWebApp; MyWebApp cURL's the file further to SomeServer, getting the response. Opt.2 — JS magic The smart way it could be perfect: User uploads the file directly to SomeServer, from within an iFrame; MyWebApp gets the response through JavaScript. But this is(?) impossible due to the 'Same Origin Policy', isn't it? Opt. 3 — nginx proxying? The better way for a production server: User uploads files to MyWebApp; nginx intercepts the file uploads and sends them directly to the SomeServer; JSON response is also intercepted by nginx and processed by MyWebApp. Does this make any sense, and what would be the nginx config for, say, /fileupload Location to proxy it to SomeServer ?

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  • Updating a local sqlite db that is used for local metadata & caching from an service?

    - by Pharaun
    I've searched through the site and haven't found a question/answer that quite answer my question, the closest one I found was: Syncing objects between two disparate systems best approach. Anyway to begun, because there is no RSS feeds available, I'm screen scrapping a webpage, hence it does a fetch then it goes through the webpage to scrap out all of the information that I'm interested in and dumps that information into a sqlite database so that I can query the information at my leisure without doing repeat fetching from the website. However I'm also storing various metadata on the data itself that is stored in the sqlite db, such as: have I looked at the data, is the data new/old, bookmark to a chunk of data (Think of it as a collection of unrelated data, and the bookmark is just a pointer to where I am in processing/reading of the said data). So right now my current problem is trying to figure out how to update the local sqlite database with new data and/or changed data from the website in a manner that is effective and straightforward. Here's my current idea: Download the page itself Create a temporary table for the parsed data to go into Do a comparison between the official and the temporary table and copy updates and/or new information to the official table This process seems kind of complicated because I would have to figure out how to determine if the data in the temporary table is new, updated, or unchanged. So I am wondering if there isn't a better approach or if anyone has any suggestion on how to architecture/structure such system?

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  • Why does Tex/Latex not speed up in subsequent runs?

    - by Debilski
    I really wonder, why even recent systems of Tex/Latex do not use any caching to speed up later runs. Every time that I fix a single comma*, calling Latex costs me about the same amount of time, because it needs to load and convert every single picture file. (* I know that even changing a tiny comma could affect the whole structure but of course, a well-written cache format could see the impact of that. Also, there might be situations where 100% correctness is not needed as long as it’s fast.) Is there something in the language of Tex which makes this complicated or impossible to accomplish or is it just that in the original implementation of Tex, there was no need for this (because it would have been slow anyway on those large computers)? But then on the other hand, why doesn’t this annoy other people so much that they’ve started a fork which has some sort of caching (or transparent conversion of Tex files to a format which is faster to parse)? Is there anything I can do to speed up subsequent runs of Latex? Except from putting all the stuff into chapterXX.tex files and then commenting them out?

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  • What languages should a microISV use to write commercial software?

    - by Wal
    I've been writing software in Java for many years now, but it was always for internal applications that would be deployed to a server. I'd like to get into writing desktop applications now but I don't know where to start. I've written a few Java/Swing applications but again they were for internal use. My understanding is that Java and other semi-compiled and interpreted languages are too easy to reverse engineer, making them unsuitable for commercial software. I am aware that there are compilers for Java and some other interpreted language, but I've also heard that they are pricey and/or unreliable. Assuming I start a microISV and wish to develop and sell applications to a broad audience, what's my best bet? I would prefer something that can be written close to once, and compiled for different operating systems but I am not opposed to .NET and a Windows-only audience if other languages would compromise the experience (installation ease & user experience) in Windows. My only issue there is that I don't have a large starting budget and paying out the wazoo for the required development tools is not really in the cards.

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  • MySQL DDL error creating tables

    - by Alexandstein
    I am attempting to create tables for a MySQL database, but I am having some syntactical issues. It would seem that syntax checking is behaving differently between tables for some reason. While I've gotten all the other tables to go through, the table, 'stock' doesn't seem to be working, despite seeming to use the same syntax patterns. CREATE TABLE users ( user_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, username VARCHAR(30) NOT NULL, password CHAR(41) NOT NULL, date_joined DATETIME NOT NULL, funds DOUBLE UNSIGNED NOT NULL, PRIMARY KEY(user_id), UNIQUE KEY(username) ); CREATE TABLE owned_stocks ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, user_id SMALLINT UNSIGNED NOT NULL, paid_price DOUBLE UNSIGNED NOT NULL, quantity MEDIUMINT UNSIGNED NOT NULL, purchase_date DATETIME NOT NULL, PRIMARY KEY(id) ); CREATE TABLE tracking_stocks ( ticker VARCHAR(5) NOT NULL, user_id SMALLINT UNSIGNED NOT NULL, PRIMARY KEY(ticker) ); CREATE TABLE stocks ( ticker VARCHAR(5) NOT NULL, last DOUBLE UNSIGNED NOT NULL, high DOUBLE UNSIGNED NOT NULL, low DOUBLE UNSIGNED NOT NULL, company_name VARCHAR(30) NOT NULL, last_updated INT UNSIGNED NOT NULL, change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, PRIMARY KEY(ticker) ); Am I just missing a really obvious syntactical issue? ERROR: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, last DOUBLE' at line 4

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  • When to choose which machine learning classifier?

    - by LM
    Suppose I'm working on some classification problem. (Fraud detection and comment spam are two problems I'm working on right now, but I'm curious about any classification task in general.) How do I know which classifier I should use? (Decision tree, SVM, Bayesian, logistic regression, etc.) In which cases is one of them the "natural" first choice, and what are the principles for choosing that one? Examples of the type of answers I'm looking for (from Manning et al.'s "Introduction to Information Retrieval book": http://nlp.stanford.edu/IR-book/html/htmledition/choosing-what-kind-of-classifier-to-use-1.html): a. If your data is labeled, but you only have a limited amount, you should use a classifier with high bias (for example, Naive Bayes). [I'm guessing this is because a higher-bias classifier will have lower variance, which is good because of the small amount of data.] b. If you have a ton of data, then the classifier doesn't really matter so much, so you should probably just choose a classifier with good scalability. What are other guidelines? Even answers like "if you'll have to explain your model to some upper management person, then maybe you should use a decision tree, since the decision rules are fairly transparent" are good. I care less about implementation/library issues, though. Also, for a somewhat separate question, besides standard Bayesian classifiers, are there 'standard state-of-the-art' methods for comment spam detection (as opposed to email spam)? [Not sure if stackoverflow is the best place to ask this question, since it's more machine learning than actual programming -- if not, any suggestions for where else?]

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