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  • Rendering 'belongs_to" in index view question - Ruby on Rails

    - by bgadoci
    I have created a simple blog application with Ruby on Rails. The applications consists of two tables, posts and comments. Comments belongs_to :post and posts has_many :comments. I created posts table with the following columns: title:string, body:text. I created the comments table with the following columns: body:text post_id:integer name:string email:string In the /views/comments/index.html.erb display I would like to show a listing of all comments w/ the post title as well. Currently, the index view only displays post_id, body, name, email. How do I replace the post_id column with the corresponding post title? Here is my code: CommentsController Index action: def index @comments = Comment.all :order => "created_at DESC" respond_to do |format| format.html # index.html.erb format.xml { render :xml => @comments } format.json { render :json => @comments } format.atom end end /views/comments/index.html.erb <h1>Listing comments</h1> <table> <tr> <th>Post</th> <th>Body</th> </tr> <% @comments.each do |comment| %> <tr> <td><%=h comment.post_id %></td> <td><%=h comment.body %></td> <td><%=h comment.name %></td> <td><%=h comment.email %></td> </tr> <% end %> </table> <br />

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  • C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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  • Is there a browser independet bookmarktool supporting tags, date and free comments?

    - by bernd_k
    I am looking for a tool, which helps me to organize my personal bookmarks. I want to be able to assign tags and free comments to a bookmark. I want to search my bookmarks by tags date of bookmarking pattern in title pattern in url It would be nice to be web based to enable sharing my bookmarks between different machines. But for it would be OK, if it works on a single machine as long as it has some import/export way to transfer the links to a new machine replacing the old. As browsers I'm using Firefox and ChromePlus. It would be nice, if the solution works with both browsers. With free comments, I mean additional remarks stored for a bookmark, which is not essential for searching.

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  • MySQL Subquery LIMIT

    - by atif089
    As the title says, I wanted a workaround for this... SELECT comments.comment_id, comments.content_id, comments.user_id, comments.`comment`, comments.comment_time, NULL FROM comments WHERE (comments.content_id IN (SELECT content.content_id FROM content WHERE content.user_id = 1 LIMIT 0, 10)) Cheers

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  • https://www.googleapis.com/drive/v2/files/<fileid>/comments?alt=json returned "Not Found" on a file that can't be opened

    - by Kartik Ayyar
    More details as below: https://www.googleapis.com/drive/v2/files/1iNMGIAFXuhS_CO_hnEO0_EJ9PAgT-hXYqWYv0MPGUTI/comments?alt=json returned "Not Found The file is present in drive and shows in drive.changes.list, but can't be opened in Google Drive either. There are two problems here a) the file is somehow corrupt ( it was a document imported into drive, so that failed, but that isn't something I care about for the purposes of this question ) b) The file shows up as existing in some API calls, but calls to read comments with the Drive SDK comments API fail. Here are results from an API call showing how the file does indeed exist: "file": { "kind": "drive#file", "id": "1iNMGIAFXuhS_CO_hnEO0_EJ9PAgT-hXYqWYv0MPGUTI", "etag": "\"o35FABD0TC3H-Up3OL3UA9kEB2w/MTM3MTc2NzU5NzEyNA\"", .... .... "iconLink": "https://ssl.gstatic.com/docs/doclist/images/icon_11_document_list.png", "title": "<removed>", "mimeType": "application/vnd.google-apps.document", "labels": { "starred": false, "hidden": false, "trashed": true, "restricted": false, "viewed": true },

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  • Why it is necessary to put comments on check-ins? [closed]

    - by Mik Kardash
    In fact, I always have something to put in when I perform a check-in of my code. However, the question I have is - Is it really so necessary? Does it help so much? How? From one point of view, comments can help you to keep track of changes performed with every check-in. Thus, I will be able to analyze the changes and identify a hypothetic problem a little bit quicker. On the other hand, it takes some time to write useful information into check-in. Is it worth it? What are the pros and cons of writing comments to every check-in? Is there any way to write "efficient" check-in comments?

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  • How to implement partial refresh like facebook like/comments?

    - by shillong
    We have java web application. Summary page will display list of rows. For each row, user can vote and add comments. Vote or add comments will commit immediately and refresh total vote number and comments count. We want to refresh current row instead of whole table just like Facebook does. If need, we can show the list of data with form format (iterator List of data) instead of table format. How to implement this feature base on JSF?

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  • Documentation for Qt documentation comments? Qt + Doxygen?

    - by Jake Petroules
    Where can I find documentation for Qt documentation comments? I'm referring to how Qt uses a specific style for documentation comments, like so: /*! \class MyClassName \brief The MyClassName class is used as an example on Stack Overflow. This class serves a few functions, the most important being: \list \i So people can understand my question. \i So people can have a few laughs at the comedy in my example. \endlist */ ...you get the picture. So where can I find information about all the switches, like \class, \list, \brief, etc. Also, what tool(s) do I use to generate documentation files from these comments in my source files? Does Doxygen support this syntax?

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  • Need help with a sub query/group/order (get latest comment for each ordered topic)

    - by Scarface
    Hey guys I have a query that currently finds the latest comment for each of a user's topics and then orders topics by that comment's timestamp. What I want to do is expand on this query's use and print the latest comment for each topic. The problem with this query is that while it orders the topics correctly, it prints seemingly random comments for each topic. I am trying to implement a sub query but I am not quite sure how to approach it. I was thinking that I just had to somehow use this query to get the comments. If anyone has any ideas I would really appreciate it. Here is what I think I need to add SELECT * FROM comments where topic_id='$topic_id' ORDER BY timestamp DESC LIMIT 1 Here is the query I need to modify SELECT topic.topic_title, topic.content_type, topic.subject_id, topic.creator, topic.description, topic.topic_id,comments.message,comments.user FROM comments JOIN topic ON topic.topic_id = comments.topic_id WHERE topic.creator = '$user' AND comments.timestamp > $week GROUP BY topic_id ORDER BY MAX(comments.timestamp) DESC

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  • Will adsense 'use' comments between the adsense opening and closing tags for ad targeting?

    - by SuperSpy
    I've got a simple website on which students of my school can see their timetable. I setup adsense three weeks ago and everything is working fine. But I would like to help adsense. Since only a timetable and a few instructions are shown, there is scarcely content to which ads can relate. Idea: <!- google_ad_section_start –> <!-- Students like clothing ... and bargains, etc.--> <!– google_ad_section_end –> Will this work? Or are there other ways to help adsense?

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  • Threaded Django task doesn't automatically handle transactions or db connections?

    - by Gabriel Hurley
    I've got Django set up to run some recurring tasks in their own threads, and I noticed that they were always leaving behind unfinished database connection processes (pgsql "Idle In Transaction"). I looked through the Postgres logs and found that the transactions weren't being completed (no ROLLBACK). I tried using the various transaction decorators on my functions, no luck. I switched to manual transaction management and did the rollback manually, that worked, but still left the processes as "Idle". So then I called connection.close(), and all is well. But I'm left wondering, why doesn't Django's typical transaction and connection management work for these threaded tasks that are being spawned from the main Django thread?

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  • Can I safely bind to data on multi-threaded applications?

    - by Paul
    Hi everyone, I'm trying to solve a classic problem - I have a multi-threaded application which runs some processor-intensive calculations, with a GUI interface. Every time one of the threads has completed a task, I'd like to update a status on a table taskID | status I use DataGridView and BindingList in the following way: BindingList<Task> tasks; dataGridView.DataSource = tasks public class Task : INotifyPropertyChanged { ID{get;} Status{get;set;} } Can a background thread safely update a task's status? and changes will be seen in the correct order in the GUI? Second Question: When do I need to call to PropertyChanged? I tried running with and without the call, didn't seem to bother.. Third Question: I've seen on MSDN that dataGridView uses BindingSource as a mediator between DataGridView.DataSource and BindingList Is this really necessary?

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  • Visual Studio: Collapse Methods, but not Comments (Summary etc.)

    - by Alex
    Hello, is there a way (settings? "macro"? extension?) that I can simply toggle outlining so that only the using section and my methods collapse to their signature line, but my comments (summary and double slash comments) and classes stay expanded? Examples: 1) Uncollapsed using System; using MachineGun; namespace Animals { /// <summary> /// Angry animal /// Pretty Fast, too /// </summary> public partial class Lion { // // Dead or Alive public Boolean Alive; /// <summary> /// Bad bite /// </summary> public PieceOfAnimal Bite(Animal animalToBite) { return animalToBite.Shoulder; } /// <summary> /// Fatal bite /// </summary> public PieceOfAnimal Kill(Animal animalToKill) { return animalToKill.Head; } } } 2) Collapsed (the following is my desired result): using[...] namespace Animals { /// <summary> /// Angry animal /// Pretty Fast, too /// </summary> public partial class Lion { // // Dead or Alive public Boolean Alive; /// <summary> /// Bad bite /// </summary> public PieceOfAnimal Bite(Animal animalToBite)[...] /// <summary> /// Fatal bite /// </summary> public PieceOfAnimal Kill(Animal animalToKill)[...] } } This is how I prefer seeing my class files (the collapsed form). I've been doing the collapsing by hand a million times by now and I think there should be a way to automate/customize/extend VS to do it the way I want? Every time I debug/hit a breakpoint, it uncollapses and messes up things. If I collapse via the context menu's collapse to outline etc. it also collapses my comments which isn't desired. Appreciate your help!

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  • Get your content off Blogger.com

    - by Daniel Moth
    Due to blogger.com deprecating FTP users I've decided to move my blog. When I think of the content of a blog, 4 items come to mind: blog posts, comments, binary files that the blog posts linked to (e.g. images, ZIP files) and the CSS+structure of the blog. 1. Binaries The binary files you used in your blog posts are sitting on your own web space, so really blogger.com is not involved with that. Nothing for you to do at this stage, I'll come back to these in another post. 2. CSS and structure In the best case this exists as a separate CSS file on your web space (so no action for now) or in a worst case, like me, your CSS is embedded with the HTML. In the latter case, simply navigate from you dashboard to "Template" then "Edit HTML" and copy paste the contents of the box. Save that locally in a txt file and we'll come back to that in another post. 3. Blog posts and Comments The blog posts and comments exist in all the HTML files on your own web space. Parsing HTML files to extract that can be painful, so it is easier to download the XML files from blogger's servers that contain all your blog posts and comments. 3.1 Single XML file, but incomplete The obvious thing to do is go into your dashboard "Settings" and under the "Basic" tab look at the top next to "Blog Tools". There is a link there to "Export blog" which downloads an XML file with both comments and posts. The problem with that is that it only contains 200 comments - if you have more than that, you will lose the surplus. Also, this XML file has a lot of noise, compared to the better solution described next. (note that a tool I will refer to in a future post deals with either kind of XML file) 3.2 Multiple XML files First you need to find your blog ID. In case you don't know what that is, navigate to the "Template" as described in section 2 above. You will find references to the blog id in the HTML there, but you can also see it as part of the URL in your browser: blogger.com/template-edit.g?blogID=YOUR_NUMERIC_ID. Mine is 7 digits. You can now navigate to these URLs to download the XML for your posts and comments respectively: blogger.com/feeds/YOUR_NUMERIC_ID/posts/default?max-results=500&start-index=1 blogger.com/feeds/YOUR_NUMERIC_ID/comments/default?max-results=200&start-index=1 Note that you can only get 500 posts at a time and only 200 comments at a time. To get more than that you have to change the URL and download the next batch. To get you started, to get the XML for the next 500 posts and next 200 comments respectively you’d have to use these URLs: blogger.com/feeds/YOUR_NUMERIC_ID/posts/default?max-results=500&start-index=501 blogger.com/feeds/YOUR_NUMERIC_ID/comments/default?max-results=200&start-index=201 ...and so on and so forth. Keep all the XML files in the same folder on your local machine (with nothing else in there). 4. Validating the XML aka editing older blog posts The XML files you just downloaded really contain HTML fragments inside for all your blog posts. If you are like me, your blog posts did not conform to XHTML so passing them to an XML parser (which is what we will want to do) will result in the XML parser choking. So the next step is to fix that. This can be no work at all for you, or a huge time sink or just a couple hours of pain (which was my case). The process I followed was to attempt to load the XML files using XmlDocument.Load and wait for the exception to be thrown from my code. The exception would point to the exact offending line and column which would help me fix the issue. Rather than fix it in the XML itself, I would go back and edit the offending blog post and fix it there - recommended! Then I'd repeat the cycle until the XML could be loaded in the XmlDocument. To give you an idea, some of the issues I encountered are: extra or missing quotes in img and href elements, direct usage of chevrons instead of encoding them as &lt;, missing closing tags, mismatched nested pairs of elements and capitalization of html elements. For a full list of things that may go wrong see this. 5. Opportunity for other changes I also found a few posts that did not have a category assigned so I fixed those too. I took the further opportunity to create new categories and tag some of my blog posts with that. Note that I did not remove/change categories of existing posts, but only added.   In an another post we'll see how to use the XML files you stored in the local folder… Comments about this post welcome at the original blog.

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  • How can I improve my real-time behavior in multi-threaded app using pthreads and condition variables

    - by WilliamKF
    I have a multi-threaded application that is using pthreads. I have a mutex() lock and condition variables(). There are two threads, one thread is producing data for the second thread, a worker, which is trying to process the produced data in a real time fashion such that one chuck is processed as close to the elapsing of a fixed time period as possible. This works pretty well, however, occasionally when the producer thread releases the condition upon which the worker is waiting, a delay of up to almost a whole second is seen before the worker thread gets control and executes again. I know this because right before the producer releases the condition upon which the worker is waiting, it does a chuck of processing for the worker if it is time to process another chuck, then immediately upon receiving the condition in the worker thread, it also does a chuck of processing if it is time to process another chuck. In this later case, I am seeing that I am late processing the chuck many times. I'd like to eliminate this lost efficiency and do what I can to keep the chucks ticking away as close to possible to the desired frequency. Is there anything I can do to reduce the delay between the release condition from the producer and the detection that that condition is released such that the worker resumes processing? For example, would it help for the producer to call something to force itself to be context switched out? Bottom line is the worker has to wait each time it asks the producer to create work for itself so that the producer can muck with the worker's data structures before telling the worker it is ready to run in parallel again. This period of exclusive access by the producer is meant to be short, but during this period, I am also checking for real-time work to be done by the producer on behalf of the worker while the producer has exclusive access. Somehow my hand off back to running in parallel again results in significant delay occasionally that I would like to avoid. Please suggest how this might be best accomplished.

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  • Blog comment spammers &hellip; help!

    - by Steve Clements
    Hey, I need some advice/help, now I’ve been writing on this blog for a few years, I don’t blog a great deal in comparison to many of my peers and my blog doesn’t get a massive number of hits, BUT I seem to get a fair share of comments spammers!! I have an image verification on the comments and I have put an Akismet API key into the Geekswithblogs settings, but I still get a bunch of spam comments. They could almost be real, until you see the link going off to some dating site or casino crap. What does everyone do?? Delete them every time?? Moderate comments?? I would rather not moderate comments if possible, but is that the only way to stop the crap?? Thx Technorati Tags: spammers,comments,help

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  • syntax error in sql query?

    - by user1550588
    I want to create some tables in database so for that i wright some queries to create table. but i got an error "there was a syntax error in your sql statement". I check all my queries but i am not able to find what syntax i wright wrong. here i attached my sql queries please told me what is wrong with queries. Thanks in advance. CREATE TABLE "WATER&SEWAGE" { "CUSTOMER_ID" VARCHAR, "POTABLE_WATER" VARCHAR, "HOT_WATER" VARCHAR, "SAFETY" VARCHAR, "T/P_VALVE+EXT" VARCHAR, "HEATER_TYPE" VARCHAR, "GAS_VENT_CONDITION" VARCHAR, "FIRE_BOX_CONDITION" VARCHAR, "PRESSURE" VARCHAR, "BACK_FLOW" VARCHAR, "PLUMBING_CONDITION" VARCHAR, "CABINET_CONDITION" VARCHAR, "3_COMP_SINK" VARCHAR, "WATER_HEATER" VARCHAR, "CLEAN_OUT_CONDITION" VARCHAR, "FLOOR_DRAIN" VARCHAR, "FLOOR_SINK" VARCHAR, "MAINTANANCE" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "TIME_AND_TETMPERATURE_REL" ("CUSTOMER_ID" INTEGER, "THERMOMTE_AVAILABLE" VARCHAR, "THERMO_TYPE" VARCHAR, "COLD_TEMP" VARCHAR, "FOOD_TYPE1" VARCHAR, "PROPER_COOLING" VARCHAR, "FOOD_TYPE2" VARCHAR, "COMPLIANCE" VARCHAR, "FOOD_TYPE3" VARCHAR, "TPHC" VARCHAR, "HACCP" VARCHAR, "HOT_HOLDING_TEMP" VARCHAR, "FOOD_TYPE4" VARCHAR, "HOT_TEMP" VARCHAR, "FOOD_TYPE5" VARCHAR, "IMPROPER_REHEATING" VARCHAR, "FOOD_TYPE6" VARCHAR, "FOOD_OUT_OF_TEMP" VARCHAR, "WRITTEN_PLAN_FILES" VARCHAR, "EMPLOYEE_KNOWLEDGE" VARCHAR, "TIME_KEEPING_METHODS" VARCHAR, "HACCP_METHODS" VARCHAR, "CALIBRATION" VARCHAR, "COOKING_TEMP" VARCHAR, "EQUIP_CONDITION" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "PROTECTION_FROM_CONTAMINATION" ("FOOD_ADULTERATION" VARCHAR, "FOOD_SPOILAGE" VARCHAR, "CONTAMINATION" VARCHAR, "FOOD_STORAGE" VARCHAR, "REFRIGRATORS" VARCHAR, "FREEZER" VARCHAR, "FIFO" VARCHAR, "DRY" VARCHAR, "DISHWASHING_CHEMICALS" VARCHAR, "CLEANING" VARCHAR, "SANITIZER" VARCHAR, "SUPPLY_EQUIPMENT" VARCHAR, "PESTICIDES" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR, "CUSTOMER_ID" INTEGER) CREATE TABLE "PHYSICAL_FACILITIES_2" ("CUSTOMER_ID" VARCHAR, "CEILING" VARCHAR, "WINDOWS" VARCHAR, "SPOILS_STORAGE" VARCHAR, "DOORS" VARCHAR, "PERSONAL_LOCKERS" VARCHAR, "FLOORS" VARCHAR, "CONDITION" VARCHAR, "HANDICAP" VARCHAR, "SELF_CLOSING_ROOM" VARCHAR, "TOILETS" VARCHAR, "TOILET_PAPER" VARCHAR, "TOILET_CONDITION" VARCHAR, "VENTILATION_CONDITION" VARCHAR, "MENS" VARCHAR, "MEN'S_VENTILATION" VARCHAR, "MEN'S_FLOOR_DRAWN" VARCHAR, "MEN'S_TOILET_STALLS" VARCHAR, "MEN'S_HAND_SINK" VARCHAR, "MEN'S_TOWELS" VARCHAR, "WOMEN'S" VARCHAR, "WOMEN'S_VENTILATION" VARCHAR, "WOMEN'S_FLOOR_DRAWN" VARCHAR, "WOMEN'S_TOILET_STALLS" VARCHAR, "WOMEN'S_HAND_SINK" VARCHAR, "WOMEN'S_TOWELS" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "PHYSICAL_FACILITIES_1" ("CUSTOMER_ID" VARCHAR, "LIGHTNING" VARCHAR, "KITCHEN" VARCHAR, "STORAGE" VARCHAR, "REFRIGRATION" VARCHAR, "JANITORIAL" VARCHAR, "INTERIOR" VARCHAR, "FIXTURE" VARCHAR, "FOOTCANDLES_1" VARCHAR, "FOOTCANDLES_2" VARCHAR, "FOOTCANDLES_3" VARCHAR, "FOOTCANDLES_4" VARCHAR, "FOOTCANDLES_5" VARCHAR, "EXTERIOR" VARCHAR, "WINDOWS" VARCHAR, "GLASS" VARCHAR, "SCREEN" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "PEST_CONTROL" ("CUSTOMER_ID" VARCHAR, "WALL/CEILING_PIPES" VARCHAR, "SANITATION" VARCHAR, "DOORS" VARCHAR, "SELF_CLOSING" VARCHAR, "RODENT_PROOF" VARCHAR, "VERMIN_PROOFING" VARCHAR, "FOUNDATION" VARCHAR, "ATTIC_VENTS" VARCHAR, "WINDOWS" VARCHAR, "TYPE_SCREENS" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "GENERAL_FOOD_SAFETY_REQ" ("CUSTOMER_ID" VARCHAR, "APPROVED_METHODS" VARCHAR, "DEFROST" VARCHAR, "FROZEN_FOOD" VARCHAR, "FOOD_WASHING" VARCHAR, "PRODUCE_1" VARCHAR, "FRUITS" VARCHAR, "GRAINS" VARCHAR, "VEGETABLES" VARCHAR, "SEPERATE_FROM_CONT" VARCHAR, "RAW" VARCHAR, "PRODUCE_2" VARCHAR, "STORED_BULK" VARCHAR, "STORAGE" VARCHAR, "FIFO" VARCHAR, "REFRIGRATAION" VARCHAR, "STORAGE_TEMP" VARCHAR, "HUMIDITY" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "FOOD_SAFETY_CERTIFICATION" ("CUSTOMER_ID" INTEGER,"OWNER" VARCHAR,"MANAGER" VARCHAR,"EMPLOYEE" VARCHAR,"NAME1" VARCHAR,"NAT'L_REGISTRY1" VARCHAR,"PROMETRIC1" VARCHAR,"SERVESAFE1" VARCHAR,"EXPIRATION1" VARCHAR,"NAME2" VARCHAR,"NAT'L_REGISTRY2" VARCHAR,"PROMETRIC2" VARCHAR,"SERVESAFE2" VARCHAR,"EXPIRATION2" VARCHAR,"COMMENTS" VARCHAR,"FOOD_TEMP" VARCHAR,"DISHWASHER" VARCHAR,"DANGER_ZONE" VARCHAR,"COOLING_FOODS" VARCHAR,"THAWING" VARCHAR,"REHEATING" VARCHAR,"THERMOMETERS" VARCHAR,"FIFO" VARCHAR,"HANDWASH" VARCHAR,"COOKING_TEMP" VARCHAR,"FOOD_POISONING_TYPES" VARCHAR,"EVEDENCE_PHOTOS" VARCHAR) CREATE TABLE "FOOD_FROM_APPROVED_SOURCES" ("CUSTOMER_ID" VARCHAR, "RECEIPTS" VARCHAR, "DELIVERY_DOOR" VARCHAR, "AIR_CURTAIN" VARCHAR, "VELOCITY" VARCHAR, "OFF_LOAD" VARCHAR, "INSPECTS" VARCHAR, "RODENTS" VARCHAR, "WARNING" VARCHAR, "SHELL_FISH" VARCHAR, "GULF_OYSTER" VARCHAR, "FOOD_OUT_OF_TEMP" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTO" VARCHAR) CREATE TABLE "FOOD_FACILITY_SITE_FACTS" ("CUSTOMER_ID" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL UNIQUE,"DBA" VARCHAR,"DISTRICT" VARCHAR,"CITY" VARCHAR,"ZIPCODE" VARCHAR,"ADDRESS" VARCHAR,"SEAT_NO" VARCHAR,"PHONE_NO" VARCHAR,"OWNER" VARCHAR,"PERSON_IN_CHARGE" VARCHAR,"WEBSITE" VARCHAR,"EMAIL" VARCHAR,"FACILITY_TYPE" VARCHAR,"SQ_FOOTAGE" VARCHAR,"NO_OF_SEATS" VARCHAR,"ALCOHOL_SALES" VARCHAR,"LTD_PREP" VARCHAR,"BUSINESS_LICENCE_NO" VARCHAR,"EXPIRATION" VARCHAR,"COMMENTS" VARCHAR,"EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "FOOD_DISPLAY_SELF_SERVICE" ("CUSTOMER_ID" VARCHAR, "SELF_SERVICE" VARCHAR, "LIDS" VARCHAR, "UTENSILS" VARCHAR, "HOW_OFTEN_CHANGED" VARCHAR, "SCOOP" VARCHAR, "SNEEZ_GUARD" VARCHAR, "DISHES" VARCHAR, "CROSS" VARCHAR, "SENITATION" VARCHAR, "MAINTANANCE" VARCHAR, "MECHANICAL_CONDITION" VARCHAR, "SERVICE_OF_UTENSIL" VARCHAR, "TIME" VARCHAR, "PRPER_FOOD_LABELING" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "EQUIPMENT/UTENSILS/LINES" ("CUSTOMER_ID" VARCHAR, "STORED_DISHES" VARCHAR, "CUPS" VARCHAR, "DAMAGED_DISHES" VARCHAR, "UTENSILS" VARCHAR, "LINES" VARCHAR, "COOLING_EQUIPMENT" VARCHAR, "COOK_WARE_STORAGE" VARCHAR, "CONDITION" VARCHAR, "STORAGE_LOCATION" VARCHAR, "NAPKINS" VARCHAR, "SANITATION" VARCHAR, "ADEQUATE_CAPACITY" VARCHAR, "HAZARDS" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "EMPLOYEE_HEALTH_AND_HYGENE" ("CSTOMER_ID" INTEGER, "COMUNICABLE_DIESEASE" VARCHAR, "WIPING_BAGS" VARCHAR, "DISCHARGE" VARCHAR, "LOCKERS" VARCHAR, "PROPER_HAND_WASH" VARCHAR, "RESTROOM_CONDITION" VARCHAR, "HANDWASH_STATION" VARCHAR, "HAIR_RESTRAINT" VARCHAR, "GLOVES_USED" VARCHAR, "WOUND_CARE" VARCHAR, "FOOD_SAMPLE_TESTING" VARCHAR, "GARMENT_CONDITION" VARCHAR, "HEALTH" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "DISH&WARE_WASHING" ("CUSTOMER_ID" INTEGER, "TYPE_OF_COMPARTMENT_SINK" VARCHAR, "PLUMBING_ISSUE1" VARCHAR, "QUATERNARY_AMMONIA" VARCHAR, "IODINE" VARCHAR, "HOT_WTR_SANIT_TEMP" VARCHAR, "PLUMBING_ISSUE2" VARCHAR, "HOT_WATER" VARCHAR, "TEMP" VARCHAR, "DISHWASHER_TYPE" VARCHAR, "WAQLL_CONDITION" VARCHAR, "SANITIZER_LEVELS" VARCHAR, "CHLORINE" VARCHAR, "SINK_OR_DISHWASHER" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR) CREATE TABLE "CORRECTIVE_ACTIONS" ("CUSTOMER_ID" VARCHAR, "CORRECTIVE_ACTIONS" VARCHAR) CREATE TABLE "CONSUMER_ADVISORY" ("CUSTOMER_ID" VARCHAR, "TRUTH_IN_MENU" VARCHAR, "MAJOR_CHAIN" VARCHAR, "TRANS_FAT" VARCHAR, "SCHOOL" VARCHAR, "PROHIBITED" VARCHAR, "CALORIES" VARCHAR, "COMMENTS" VARCHAR, "EVEDINCE_PHOTOS" VARCHAR) CREATE TABLE "COMPLAINS&ENFORCEMENTS" ("CUSTOMER_ID" VARCHAR, "PLAN_SUBMITTED" VARCHAR, "APPROVEL" VARCHAR, "CERTIFICATE_OF_OCCU" VARCHAR, "PRIOR_INSPEK_REPORT" VARCHAR, "LAST_INSPECTION_DATE" VARCHAR, "PERMIT_STATUS" VARCHAR, "POSTED" VARCHAR, "EXPIRATION" VARCHAR, "PERMIT_DISPLAYED" VARCHAR, "INSPECTION_REPORT_POSTING" VARCHAR, "COMMENTS" VARCHAR, "EVIDENCE_PHOTOS" VARCHAR)

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  • Handling user interface in a multi-threaded application (or being forced to have a UI-only main thre

    - by Patrick
    In my application, I have a 'logging' window, which shows all the logging, warnings, errors of the application. Last year my application was still single-threaded so this worked [quite] good. Now I am introducing multithreading. I quickly noticed that it's not a good idea to update the logging window from different threads. Reading some articles on keeping the UI in the main thread, I made a communication buffer, in which the other threads are adding their logging messages, and from which the main thread takes the messages and shows them in the logging window (this is done in the message loop). Now, in a part of my application, the memory usage increases dramatically, because the separate threads are generating lots of logging messages, and the main thread cannot empty the communication buffer quickly enough. After the while the memory decreases again (if the other threads have finished their work and the main thread gradually empties the communication buffer). I solved this problem by having a maximum size on the communication buffer, but then I run into a problem in the following situation: the main thread has to perform a complex action the main thread takes some parts of the action and let's separate threads execute this while the seperate threads are executing their logic, the main thread processes the results from the other threads and continues with its work if the other threads are finished Problem is that in this situation, if the other threads perform logging, there is no UI-message loop, and so the communication buffer is filled, but not emptied. I see two solutions in solving this problem: require the main thread to do regular polling of the communication buffer only performing user interface logic in the main thread (no other logic) I think the second solution seems the best, but this may not that easy to introduce in a big application (in my case it performs mathematical simulations). Are there any other solutions or tips? Or is one of the two proposed the best, easiest, most-pragmatic solution? Thanks, Patrick

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  • Applying DDD principles in a RESTish web service

    - by Andy
    I am developing an RESTish web service. I think I got the idea of the difference between aggregation and composition. Aggregation does not enforce lifecycle/scope on the objects it references. Composition does enforce lifecycle/scope on the objects it contain/own. If I delete a composite object then all the objects it contain/own are deleted as well, while the deleting an aggregate root does not delete referenced objects. 1) If it is true that deleting aggregate roots does not necessary delete referenced objects, what sense does it make to not have a repository for the references objects? Or are aggregate roots as a term referring to what is known as composite object? 2) When you create an web service you will have multiple endpoints, in my case I have one entity Book and another named Comment. It does not make sense to leave the comments in my application if the book is deleted. Therefore, book is a composite object. I guess I should not have a repository for comments since that would break the enforcement of lifecycle and rules that the book class may have. However I have URL such as (examples only): GET /books/1/comments POST /books/1/comments Now, if I do not have a repository for comments, does that mean I have to load the book object and then return the referenced comments? Am I allowed to return a list of Comment entities from the BookRepository, does that make sense? The repository for Book may eventually become rather big with all sorts of methods. Am I allowed to write JPQL (JPA queries) that targets comments and not books inside the repository? What about pagination and filtering of comments. When adding a new comment triggered by the POST endpoint, do you need to load the book, add the comment to the book, and then update the whole book object? What I am currently doing is having a own CommentRepository, even though the comments are deleted with the book. I could need some direction on how to do it correct. Since you are exposing not only root objects in RESTish services I wonder how to handle this at the backend. I am using Hibernate and Spring.

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  • Spawn a multi-threaded Java program from a Windows command line program, spawner won't end until spa

    - by Ross Patterson
    Short version: How can I prevent a spawned Java process in Windows from blocking the spawning process from ending? Long version: I'm trying to spawn a multi-threaded Java program (Selenium RC, not that it should matter) from a program launched from the Windows command line (NAnt's <exec> task, again, not that it should matter). I'm doing it using the Windows "start" command, and the spawned process is started and runs correctly. The spawning process receives control back and finishes (NAnt says "BUILD SUCCEEDED"), but doesn't actually exit to the command line. When the spawned process finally terminates (could be hours later), the command process returns and the command line prompt occurs. For example: <target name="start_rc"> <exec program="cmd" failonerror="false" workingdir="${ross.p5.dir}\Tools\selenium\selenium-server-1.0.1" verbose="true"> <arg value="/C"/> <arg value="start"/> <arg value="java"/> <arg value="-jar"/> <arg path="${ross.p5.dir}\Tools\selenium\selenium-server-1.0.1\selenium-server.jar"/> <arg value="-userExtensions"/> <arg path="${ross.p5.dir}\Tools\selenium\selenium-server-1.0.1\user-extensions.js"/> <arg value="-browserSideLog"/> <arg value="-log"/> <arg value="${ross.p5.dir}\artifacts\selenium.log"/> <arg value="-debug"/> </exec> </target> Produces: C :\Ross>nant start_rc NAnt 0.86 (Build 0.86.2898.0; beta1; 12/8/2007) Copyright (C) 2001-2007 Gerry Shaw http://nant.sourceforge.net Buildfile: file:///C:/Ross/ross.build Target framework: Microsoft .NET Framework 3.5 Target(s) specified: start_rc start_rc: [exec] Starting 'cmd (/C start java -jar C:\p5\Tools\selenium\selenium-server-1.0.1\selenium-server.jar -userExtensions C:\p5\Tools\selenium\selenium-server-1.0.1\user-extensions.js -browserSideLog -log C:\p5\artifacts\selenium.log -debug)' in 'C:\p5\Tools\selenium\selenium-server-1.0.1' BUILD SUCCEEDED Total time: 4.1 seconds. ... and then nothing until I close the window where Java is running, then ... C:\Ross> Obviously something is preventing the nant process from terminating, but shouldn't the Windows START command prevent that?

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  • Can I avoid a threaded UDP socket in Python dropping data?

    - by 666craig
    First off, I'm new to Python and learning on the job, so be gentle! I'm trying to write a threaded Python app for Windows that reads data from a UDP socket (thread-1), writes it to file (thread-2), and displays the live data (thread-3) to a widget (gtk.Image using a gtk.gdk.pixbuf). I'm using queues for communicating data between threads. My problem is that if I start only threads 1 and 3 (so skip the file writing for now), it seems that I lose some data after the first few samples. After this drop it looks fine. Even by letting thread 1 complete before running thread 3, this apparent drop is still there. Apologies for the length of code snippet (I've removed the thread that writes to file), but I felt removing code would just prompt questions. Hope someone can shed some light :-) import socket import threading import Queue import numpy import gtk gtk.gdk.threads_init() import gtk.glade import pygtk class readFromUDPSocket(threading.Thread): def __init__(self, socketUDP, readDataQueue, packetSize, numScans): threading.Thread.__init__(self) self.socketUDP = socketUDP self.readDataQueue = readDataQueue self.packetSize = packetSize self.numScans = numScans def run(self): for scan in range(1, self.numScans + 1): buffer = self.socketUDP.recv(self.packetSize) self.readDataQueue.put(buffer) self.socketUDP.close() print 'myServer finished!' class displayWithGTK(threading.Thread): def __init__(self, displayDataQueue, image, viewArea): threading.Thread.__init__(self) self.displayDataQueue = displayDataQueue self.image = image self.viewWidth = viewArea[0] self.viewHeight = viewArea[1] self.displayData = numpy.zeros((self.viewHeight, self.viewWidth, 3), dtype=numpy.uint16) def run(self): scan = 0 try: while True: if not scan % self.viewWidth: scan = 0 buffer = self.displayDataQueue.get(timeout=0.1) self.displayData[:, scan, 0] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 1] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 2] = numpy.fromstring(buffer, dtype=numpy.uint16) gtk.gdk.threads_enter() self.myPixbuf = gtk.gdk.pixbuf_new_from_data(self.displayData.tostring(), gtk.gdk.COLORSPACE_RGB, False, 8, self.viewWidth, self.viewHeight, self.viewWidth * 3) self.image.set_from_pixbuf(self.myPixbuf) self.image.show() gtk.gdk.threads_leave() scan += 1 except Queue.Empty: print 'myDisplay finished!' pass def quitGUI(obj): print 'Currently active threads: %s' % threading.enumerate() gtk.main_quit() if __name__ == '__main__': # Create socket (IPv4 protocol, datagram (UDP)) and bind to address socketUDP = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) host = '192.168.1.5' port = 1024 socketUDP.bind((host, port)) # Data parameters samplesPerScan = 256 packetsPerSecond = 1200 packetSize = 512 duration = 1 # For now, set a fixed duration to log data numScans = int(packetsPerSecond * duration) # Create array to store data data = numpy.zeros((samplesPerScan, numScans), dtype=numpy.uint16) # Create queue for displaying from readDataQueue = Queue.Queue(numScans) # Build GUI from Glade XML file builder = gtk.Builder() builder.add_from_file('GroundVue.glade') window = builder.get_object('mainwindow') window.connect('destroy', quitGUI) view = builder.get_object('viewport') image = gtk.Image() view.add(image) viewArea = (1200, samplesPerScan) # Instantiate & start threads myServer = readFromUDPSocket(socketUDP, readDataQueue, packetSize, numScans) myDisplay = displayWithGTK(readDataQueue, image, viewArea) myServer.start() myDisplay.start() gtk.gdk.threads_enter() gtk.main() gtk.gdk.threads_leave() print 'gtk.main finished!'

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