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  • Creating a join based on data from other tables...

    - by Workshop Alex
    I'm dealing with a database structure that can be defined as "illogical". It has about 100 different schema's with all different table structures per schema. Only one common factor is a "Version" table in each schema containing about 4 fields. (Thus, there are about 100 Version tables in the database.) There's also another table (view, actually) containing a list of all the schema's in the database that have a version table. I need a stored procedure that walks through all the schema's and selects all data from the Version table, adding the schema name as a fifth field to the result. Basically, this stored procedure is to return a list of all version records per schema. My idea: first walk through the schema list to create one new SQL statements that will JOIN all the schema.version tables into one SQL statement. Then I return the result of that query. How to do this? Or does anyone have a better suggestion? (No, redesigning the structure is NOT an option.)

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  • Does the Java Memory Model (JSR-133) imply that entering a monitor flushes the CPU data cache(s)?

    - by Durandal
    There is something that bugs me with the Java memory model (if i even understand everything correctly). If there are two threads A and B, there are no guarantees that B will ever see a value written by A, unless both A and B synchronize on the same monitor. For any system architecture that guarantees cache coherency between threads, there is no problem. But if the architecture does not support cache coherency in hardware, this essentially means that whenever a thread enters a monitor, all memory changes made before must be commited to main memory, and the cache must be invalidated. And it needs to be the entire data cache, not just a few lines, since the monitor has no information which variables in memory it guards. But that would surely impact performance of any application that needs to synchronize frequently (especially things like job queues with short running jobs). So can Java work reasonably well on architectures without hardware cache-coherency? If not, why doesn't the memory model make stronger guarantees about visibility? Wouldn't it be more efficient if the language would require information what is guarded by a monitor? As i see it the memory model gives us the worst of both worlds, the absolute need to synchronize, even if cache coherency is guaranteed in hardware, and on the other hand bad performance on incoherent architectures (full cache flushes). So shouldn't it be more strict (require information what is guarded by a monitor) or more lose and restrict potential platforms to cache-coherent architectures? As it is now, it doesn't make too much sense to me. Can somebody clear up why this specific memory model was choosen? EDIT: My use of strict and lose was a bad choice in retrospect. I used "strict" for the case where less guarantees are made and "lose" for the opposite. To avoid confusion, its probably better to speak in terms of stronger or weaker guarantees.

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  • Capture data from jQuery Mobile GUI / form elements like sliders, or the flip switch/toggle, and store in a var?

    - by Carl Foggin
    I have this code, which executes without error, it shows "** slider change **" in the debug console every time the slider changes. But I cannot figure out how to capture the value of the slider so I can store it in a var. Can you help, I'm hoping it's a simple thing. $( '#page4_Options' ).live( 'pageinit', function(event){ var slideTime = userOptions.getSlideTime() / 1000; // userOptions is my Object to get/set params from localStorage. $("input[id='slider']").val(slideTime).slider("refresh"); // set default slide time when page init's. console.log("userOptions.getSlideTime()", userOptions.getSlideTime() ); $( "#slider" ).bind( "slidestop", function(event, ui) { console.log("** slider change **"); // How do I capture the new slider value into a var? }); }); Here's the HTML with the slider, it's in a tag: <div data-role="fieldcontain"> <label for="slider">Slide Duration (seconds):</label> <input type="range" name="slider" id="slider" value="2" min="0" max="60" /> </div>

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  • Web UI element to represent two different micro-views of data in the same spot?

    - by Chris McCall
    I've been tasked with laying out a portion of a screen for a customer care (call center) app that serves as sort of a header/summary block at the top of the screen. Here's what it looks like: The important part is in the red box. That little tooltip is the biz's vision for how to represent both the numeric SiteId and the textual Site Name all in the same piece of screen real estate. I asked, and the business thinks the Name is more important than the ID, but lists the Id by default, because the Name can't be truncated in the display, and there's only so much horizontal room to put the data. So they go with the Id, because it's fewer characters, and then they have the user mouse-over the Id to display the name (presumably because the tooltip can be of unlimited width and since it's floating over the rest of the screen, the full name will always be displayed. So, here's my question: Is there some better UI metaphor that I don't know about that could get this job done, while meeting the following constraints?: Does not require the mouse (uses a keyboard shortcut to do the "reveal") Allows the user to copy and paste the name Will not truncate the name Provides for the display of both the ID and name in the same spot Works with IE7

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  • Function to extract data in insert into satement for a table.

    - by user269484
    Hi...I m using this Function to extract the data but unable to extract LONG datatype. Can anyone help me? create or replace Function ExtractData(v_table_name varchar2) return varchar2 As b_found boolean:=false; v_tempa varchar2(8000); v_tempb varchar2(8000); v_tempc varchar2(255); begin for tab_rec in (select table_name from user_tables where table_name=upper(v_table_name)) loop b_found:=true; v_tempa:='select ''insert into '||tab_rec.table_name||' ('; for col_rec in (select * from user_tab_columns where table_name=tab_rec.table_name order by column_id) loop if col_rec.column_id=1 then v_tempa:=v_tempa||'''||chr(10)||'''; else v_tempa:=v_tempa||',''||chr(10)||'''; v_tempb:=v_tempb||',''||chr(10)||'''; end if; v_tempa:=v_tempa||col_rec.column_name; if instr(col_rec.data_type,'CHAR') 0 then v_tempc:='''''''''||'||col_rec.column_name||'||'''''''''; elsif instr(col_rec.data_type,'DATE') 0 then v_tempc:='''to_date(''''''||to_char('||col_rec.column_name||',''mm/dd/yyyy hh24:mi'')||'''''',''''mm/dd/yyyy hh24:mi'''')'''; else v_tempc:=col_rec.column_name; end if; v_tempb:=v_tempb||'''||decode('||col_rec.column_name||',Null,''Null'','||v_tempc||')||'''; end loop; v_tempa:=v_tempa||') values ('||v_tempb||');'' from '||tab_rec.table_name||';'; end loop; if Not b_found then v_tempa:='-- Table '||v_table_name||' not found'; else v_tempa:=v_tempa||chr(10)||'select ''-- commit;'' from dual;'; end if; return v_tempa; end; /

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  • Is a python dictionary the best data structure to solve this problem?

    - by mikip
    Hi I have a number of processes running which are controlled by remote clients. A tcp server controls access to these processes, only one client per process. The processes are given an id number in the range of 0 - n-1. Were 'n' is the number of processes. I use a dictionary to map this id to the client sockets file descriptor. On startup I populate the dictionary with the ids as keys and socket fd of 'None' for the values, i.e no clients and all pocesses are available When a client connects, I map the id to the sockets fd. When a client disconnects I set the value for this id to None, i.e. process is available. So everytime a client connects I have to check each entry in the dictionary for a process which has a socket fd entry of None. If there are then the client is allowed to connect. This solution does not seem very elegant, are there other data structures which would be more suitable for solving this? Thanks

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  • Server sends json data correctly. Client parses it wrong

    - by alois.wirkes
    I have a PHP code that generates a JSON string to send to my Android app. This part works. The problem is when my app captures that string and try to convert it into a JSONArray object. The main idea is to store that data inside a SQLite database. Here's the code that captures the JSON string: public void getPostResponse(){ try{ br = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8); sb = new StringBuilder(); line = null; while((line = br.readLine()) != null){ sb.append(line+"\n"); } is.close(); result = sb.toString(); Log.e("getPostResponse","result= "+sb.toString()); }catch(Exception e){ Log.e("log_tag","Error converting result "+e.toString()); } } And this is the result in the LogCat: 10-11 16:27:01.171: E/getPostResponse(9155): result= [{ "establecimientos":[]},{ "rutas":[]},{ "formularios":[]},{ "clientes":[]},{ "mediciones":[]}] This is why I think there's an error, the result variable should contain the whole JSON string and it doesn't. Any ideas? Variables br, sb, line and result are declared globally. JSON sent from server is already a JSONArray (starts with '[' and ends with ']'), is this what's causing the problem?

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  • Good C++ array class for dealing with large arrays of data in a fast and memory efficient way?

    - by Shane MacLaughlin
    Following on from a previous question relating to heap usage restrictions, I'm looking for a good standard C++ class for dealing with big arrays of data in a way that is both memory efficient and speed efficient. I had been allocating the array using a single malloc/HealAlloc but after multiple trys using various calls, keep falling foul of heap fragmentation. So the conclusion I've come to, other than porting to 64 bit, is to use a mechanism that allows me to have a large array spanning multiple smaller memory fragments. I don't want an alloc per element as that is very memory inefficient, so the plan is to write a class that overrides the [] operator and select an appropriate element based on the index. Is there already a decent class out there to do this, or am I better off rolling my own? From my understanding, and some googling, a 32 bit Windows process should theoretically be able address up to 2GB. Now assuming I've 2GB installed, and various other processes and services are hogging about 400MB, how much usable memory do you think my program can reasonably expect to get from the heap? I'm currently using various flavours of Visual C++.

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  • Dojo's nested BorderContainer disappear in IE

    - by h4b0
    I have this terrible problem with IE 7/8/9. I wrote an app using Dojo toolkit 1.8.0 and Play! framework. It works fine in all browser except for IE. Its 'developers tools' show no error, so does firebug. The problematic code section is here: <div data-dojo-type="dijit.layout.BorderContainer" data-dojo-props="design: 'headline'"> <div data-dojo-type="dijit.layout.ContentPane" id="head" region="top"> </div> <div data-dojo-type="dijit.layout.BorderContainer" data-dojo-props="region: 'center'"> <div data-dojo-type="dijit.layout.ContentPane" id="menu" region="left"> </div> <div data-dojo-type="dijit.layout.BorderContainer" data-dojo-props="region: 'center'"> <div data-dojo-type="dijit.layout.ContentPane" id="content_1" region="top"> </div> <div data-dojo-type="dijit.layout.ContentPane" id="content_2" region="bottom"> </div> </div> </div> <div data-dojo-type="dijit.layout.ContentPane" id="foot" region="bottom"> </div> </div> The result, in all browsers except for IE is like that: But in IE it is shown like that: Can anyone explain why there are such differences? At first I thought that in IE content is hidden, so I set overflow: auto, but no scrollbar appeared after page load.

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  • how to pull and display range (min-max) data for each page in pagination?

    - by Ty W
    I have a table of data that is searchable and sortable, but likely to produce hundreds or thousands of results for broad searches. Assuming the user searches for "foo" and sorts the foos in descending price order I'd like to show a quick-jump select menu like so: <option value="1">Page 1 ($25,000,000 - $1,625,000)</option> <option value="2">Page 2 ($1,600,000 - $1,095,000)</option> <option value="3">Page 3 ($1,095,000 - $815,000)</option> <option value="4">Page 4 ($799,900 - $699,000)</option> ... Is there an efficient way of querying for this information directly from the DB? I've been grabbing all of the matching records and using PHP to calculate the min and max value for each page which seems inefficient and likely to cause scaling problems. The only possible technique I've been able to come up with is some way of having a calculated variable that increments every X records (X records to a page), grouping by that, and selecting MIN/MAX for each page grouping... unfortunately I haven't been able to come up with a way to generate that variable.

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  • How does Haskell do pattern matching without us defining an Eq on our data types?

    - by devoured elysium
    I have defined a binary tree: data Tree = Null | Node Tree Int Tree and have implemented a function that'll yield the sum of the values of all its nodes: sumOfValues :: Tree -> Int sumOfValues Null = 0 sumOfValues (Node Null v Null) = v sumOfValues (Node Null v t2) = v + (sumOfValues t2) sumOfValues (Node t1 v Null) = v + (sumOfValues t1) sumOfValues (Node t1 v t2) = v + (sumOfValues t1) + (sumOfValues t2) It works as expected. I had the idea of also trying to implement it using guards: sumOfValues2 :: Tree -> Int sumOfValues2 Null = 0 sumOfValues2 (Node t1 v t2) | t1 == Null && t2 == Null = v | t1 == Null = v + (sumOfValues2 t2) | t2 == Null = v + (sumOfValues2 t1) | otherwise = v + (sumOfValues2 t1) + (sumOfValues2 t2) but this one doesn't work because I haven't implemented Eq, I believe: No instance for (Eq Tree) arising from a use of `==' at zzz3.hs:13:3-12 Possible fix: add an instance declaration for (Eq Tree) In the first argument of `(&&)', namely `t1 == Null' In the expression: t1 == Null && t2 == Null In a stmt of a pattern guard for the definition of `sumOfValues2': t1 == Null && t2 == Null The question that has to be made, then, is how can Haskell make pattern matching without knowing when a passed argument matches, without resorting to Eq?

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  • What is the best way to create a running integer id on the AppEngine data storage?

    - by Freed
    For various reasons, I need a unique running integer id for my entities stored on the Google AppEngine. The automatically generated key sort of has this behaviour, but it doesn't start from 1 (or 0) and doesn't guarantee that the generated integer part will come from a continuous sequence. What would be the best way to efficiently implement this on AppEngine? Is there any support from the storage system? To add to the complexity, I might need to do this over entities from different entity groups, meaning I can't just get the highest id right now and save an entity with the next id in a transaction. Might memcache be the way to go..? Edit: I havn't yet implemented this, but to clarify on the memcache idea. I know memcache is unreliable, but in practice it probably won't lose data "too often" to hurt performance. Basically, I would have a memcache entry for the last used id, update it (somehow atomically) whenever I create a new entity and use that id. In the case of memcache not having a value for this entry, I'd get the highest id so far by doing a query on my entities sorted by the id and update memcache (unless someone else had already done so). The only problem I can see with this right now would be atomicity of the operation as a whole if the save of my new entity was also part of a transaction. Thoughts..?

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  • how to clear a data in tableviewcell again start reload?

    - by Ios_learner
    i'm developing a bluetooth apps.1) I want to hide a tableview when i start the apps..after i pressed a action button i want to enable a tableview.. 2)if i again press a action button means tableviewcell clear the data and show empty before searching..give me an idea.. some of the code- - (IBAction)connectButtonTouched:(id)sender { [self.deviceTable reloadData]; self.connectButton.enabled = YES; [self.deviceTable reloadData]; peripheralManager = [[PeripheralManager alloc] init]; peripheralManager.delegate = self; [peripheralManager scanForPeripheralsAndConnect]; [self.deviceTable reloadData]; [NSTimer scheduledTimerWithTimeInterval:(float)5.0 target:self selector:@selector (connectionTimer:) userInfo:nil repeats:YES]; alert=[[UIAlertView alloc] initWithTitle:@"Bluetooth" message:@"Scanning" delegate:nil cancelButtonTitle:@"Cancel" otherButtonTitles:nil]; UIActivityIndicatorView *progress=[[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(125, 50, 30, 30)]; [alert addSubview:progress]; [progress startAnimating]; [alert show]; } tableview -(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [device count]; } -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier=@"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if(cell==nil) { cell =[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier]; } cell.textLabel.text=[device objectAtIndex:indexPath.row]; cell.accessoryType=UITableViewCellAccessoryDetailDisclosureButton; return cell; } TableView Delegate - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { UITableViewCell *cell=[tableView cellForRowAtIndexPath:indexPath]; [self performSegueWithIdentifier:@"TableDetails" sender:tableView]; }

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  • how to retrieve data from db and display it in list?

    - by raji
    In the below code I am passing catID to db.getNews(catID) super.onCreate(savedInstanceState); setContentView(R.layout.newslist); Bundle extras = getIntent().getExtras(); int catID = extras.getInt("cat_id"); mInflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE); final ListView lv = (ListView) findViewById(R.id.category); lv.setAdapter(new ArrayAdapter<String>(this, R.layout.newslist, db.getNews(catID)){ public View getView(int position, View convertView, ViewGroup parent) { View row; if (null == convertView) { row = mInflater.inflate(R.layout.newslist, null); } else { row = convertView; } TextView tv = (TextView) row.findViewById(R.id.newslist_text); tv.setText(getItem(position)); return row; } }); the getnews(int catid) function is below: public NewsItemCursor getNews(int catID) { String sql = "SELECT title FROM news WHERE catid = " + catID + " ORDER BY id ASC"; SQLiteDatabase d = getReadableDatabase(); NewsItemCursor c = (NewsItemCursor) d.rawQueryWithFactory( new NewsItemCursor.Factory(), sql, null, null); c.moveToFirst(); d.close(); return c; } But I'm getting bug as array adapter undefined... Can anyone help me to resolve this, and retrieve data to make it display in list.

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  • How to save data of two for loops in one array?

    - by Homer_Simpson
    I have two for loops and I wanna save that data in one array. The first for loop will create 5 rectangles in the array. After that, the second for loop will create 5 rectangles and add them to the array. But something doesn't work. I get that "Index was outside the bounds of the array" error message in the last line of the code and I don't know what to change. int framewidth = texture.Width / sourceRects.Length; int frameheight = texture.Height; private void vorrück(Rectangle[] sourceRects, int framewidth, int frameheight) { int doublelenght = sourceRects.Length * 2; for (int i = 0; i < sourceRects.Length; i++) sourceRects[i] = new Rectangle(i * framewidth, 0, framewidth, frameheight); for (int normallenght = sourceRects.Length; normallenght < doublelenght; normallenght++) sourceRects[normallenght] = new Rectangle((sourceRects.Length - 1 - normallenght) * framewidth, 0, framewidth, frameheight); }

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  • Prevent cached objects to end up in the database with Entity Framework

    - by Dirk Boer
    We have an ASP.NET project with Entity Framework and SQL Azure. A big part of our data only needs to be updated a few times a day, other data is very volatile. The data that barely changes we cache in memory at startup, detach from the context and than use it mainly for reading, drastically lowering the amount of database requests we have to do. The volatile data is requested everytime by a DbContext per Http request. When we do an update to the cached data, we send a message to all instances to catch a fresh version of all the data from the SQL server. So far, so good. Until we introduced a bug that linked one of these 'cached' objects to the 'volatile' data, and did a SaveChanges. Well, that was quite a mess. The whole data tree was added again and again by every update, corrupting the whole database with a whole lot of duplicated data. As a complete hack I added a completely arbitrary column with a UniqueConstraint and some gibberish data on one of the root tables; hopefully failing the SaveChanges() next time we introduce such a bug because it will violate the Unique Constraint. But it is of course hacky, and I'm still pretty scared ;P Are there any better ways to prevent whole tree's of cached objects ending up in the database? More information Project is ASP.NET MVC I cache this data, because it is mainly read only, and this saves a tons of extra database calls per http request

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  • mcsCustomscrollbar append new content not working

    - by Dariel Pratama
    i have this script in my website. $(document).ready(function(){ var comment = $('textarea[name=comment_text]').val(); var vid = $('input[name=video_id]').val(); $('#add_comment').on('click', function(){ $.post('<?php echo site_url('comment/addcomments'); ?>', $('#comment-form').serialize(), function(data){ data = JSON.parse(data); if(data.userdata){ var date = new Date(data.userdata.comment_create_time * 1000); var picture = data.userdata.user_image.length > 0 ? 'fileupload/'+data.userdata.user_image:'images/no_pic.gif'; var newComment = '<div class="row">\ <div class="col-md-4">\ <img src="<?php echo base_url(); ?>'+picture+'" class="profile-pic margin-top-15" />\ </div>\ <div class="col-md-8 no-pade">\ <p id="comment-user" class="margin-top-15">'+data.userdata.user_firstname+' '+data.userdata.user_lastname+'</p>\ <p id="comment-time">'+date.getTime()+'</p>\ </div>\ <div class="clearfix"></div>\ <div class="col-md-12 margin-top-15" id="comment-text">'+data.userdata.comment_text +'</div>\ <div class="col-md-12">\ <div class="hr-grey margin-top-15"></div>\ </div>\ </div>'; $('#comment-scroll').append($(newComment)); $('#comment').modal('hide'); } }); }); }); what i expect when a comment added to the DB and the PHP page give JSON response, the new comment will be added to the last line of $('#comment-scroll'). #comment-scroll is also have custom scroll bar by mcsCustomscrollbar. the above script also hiding the modal dialog when comment saved and it's working fine which is mean data.userdata is not empty, but why the append() isnt?

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  • Data Type Not Consistent In MS Access? (Set new field as "TEXT" but system treats it as "Yes/No" field)

    - by user3522506
    I already have an SQL command that will insert any string in the field. But it doesn't accept any string, giving me "No value given for one or more required parameters". But if my string is "Yes" or "No", it will update successfully. And in MS Access, will appear as 0 or -1 even though I set the field as text even in the beginning. Could there be any configuration I have made in my MS Access 2007? con = New OleDbConnection(cs) con.Open() Dim cb As String = "Update FS_Expenses set FS_Date=#" & dtpDate2.Text & "#,SupplierID='" & txtSupplierID.Text & "', TestField=" & Label1.Text & " where ID=" & txtID2.Text & "" cmd = New OleDbCommand(cb) cmd.Connection = con cmd.ExecuteReader() MessageBox.Show("Successfully updated!", "Record", MessageBoxButtons.OK, MessageBoxIcon.Information) con.Close() TestField is already a TEXT data type, Label1.Text value is "StringTest", will give the error. However, set Label1.Text value as = "Yes", SQL will execute successfully. Therefore, field must have not been saved as TEXT.

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  • How to open a chat window in sender and receiver side [on hold]

    - by DEEPS
    When i am trying to send a message from sender the chat window is always opening in senders side instead of receiver side.so please give a correct code to display chat box in both side. (HTML 5, JAVASCRIPT,JQUERY). This is client side code: //Send private message function sendPvtMsg(data) { var pvtmsg = data; socket.emit('message',JSON.stringify({msg: 'pvtMsg', data: { from: userName, to: toChat, pvtmsg: data }}),roomId); } socket.on('message',function(data) { var command = JSON.parse(data); var itemName = command.msg; var rec_data = command.data.message; var sender = command.data.name; //Receive message from server if (itemName == "message") { document.getElementById("chat").value += sender + " : " + rec_data + "\n"; } //Receive private message else if (itemName == "pvtMsg") { var to = command.data.to; var from = command.data.from; //To display message to sender and receiver if (userName == to || userName == from) { var pvtmsg = command.data.pvtmsg; document.getElementById("chat").value += from + "( to " + to + ")" + " : " + pvtmsg + "\n"; } } function createChatBox(chatboxtitle,minimizeChatBox) { if ($("#chatbox_"+chatboxtitle).length > 0) { if ($("#chatbox_"+chatboxtitle).css('display') == 'none') { $("#chatbox_"+chatboxtitle).css('display','block'); restructureChatBoxes(); } $("#chatbox_"+chatboxtitle+" .chatboxtextarea").focus(); return; }

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  • Asynchrony in C# 5 (Part I)

    - by javarg
    I’ve been playing around with the new Async CTP preview available for download from Microsoft. It’s amazing how language trends are influencing the evolution of Microsoft’s developing platform. Much effort is being done at language level today than previous versions of .NET. In these post series I’ll review some major features contained in this release: Asynchronous functions TPL Dataflow Task based asynchronous Pattern Part I: Asynchronous Functions This is a mean of expressing asynchronous operations. This kind of functions must return void or Task/Task<> (functions returning void let us implement Fire & Forget asynchronous operations). The two new keywords introduced are async and await. async: marks a function as asynchronous, indicating that some part of its execution may take place some time later (after the method call has returned). Thus, all async functions must include some kind of asynchronous operations. This keyword on its own does not make a function asynchronous thought, its nature depends on its implementation. await: allows us to define operations inside a function that will be awaited for continuation (more on this later). Async function sample: Async/Await Sample async void ShowDateTimeAsync() {     while (true)     {         var client = new ServiceReference1.Service1Client();         var dt = await client.GetDateTimeTaskAsync();         Console.WriteLine("Current DateTime is: {0}", dt);         await TaskEx.Delay(1000);     } } The previous sample is a typical usage scenario for these new features. Suppose we query some external Web Service to get data (in this case the current DateTime) and we do so at regular intervals in order to refresh user’s UI. Note the async and await functions working together. The ShowDateTimeAsync method indicate its asynchronous nature to the caller using the keyword async (that it may complete after returning control to its caller). The await keyword indicates the flow control of the method will continue executing asynchronously after client.GetDateTimeTaskAsync returns. The latter is the most important thing to understand about the behavior of this method and how this actually works. The flow control of the method will be reconstructed after any asynchronous operation completes (specified with the keyword await). This reconstruction of flow control is the real magic behind the scene and it is done by C#/VB compilers. Note how we didn’t use any of the regular existing async patterns and we’ve defined the method very much like a synchronous one. Now, compare the following code snippet  in contrast to the previuous async/await: Traditional UI Async void ComplicatedShowDateTime() {     var client = new ServiceReference1.Service1Client();     client.GetDateTimeCompleted += (s, e) =>     {         Console.WriteLine("Current DateTime is: {0}", e.Result);         client.GetDateTimeAsync();     };     client.GetDateTimeAsync(); } The previous implementation is somehow similar to the first shown, but more complicated. Note how the while loop is implemented as a chained callback to the same method (client.GetDateTimeAsync) inside the event handler (please, do not do this in your own application, this is just an example).  How it works? Using an state workflow (or jump table actually), the compiler expands our code and create the necessary steps to execute it, resuming pending operations after any asynchronous one. The intention of the new Async/Await pattern is to let us think and code as we normally do when designing and algorithm. It also allows us to preserve the logical flow control of the program (without using any tricky coding patterns to accomplish this). The compiler will then create the necessary workflow to execute operations as the happen in time.

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  • Could not load file or assembly 'System.Data.SQLite' or one of its dependencies. An attempt was made to load a program with an incorrect format.

    - by Om Talsania
    Problem Description: Could not load file or assembly 'System.Data.SQLite' or one of its dependencies. An attempt was made to load a program with an incorrect format. Likely to be reproduced when: You will usually encounter this problem when you have downloaded a sample application that is a 32-bit application targeted for ASP.NET 2.0 or 3.5, and you have IIS7 on a 64-bit OS running .NET 4.0, because the default setting for running 32-bit application on IIS7 with 64-bit OS is false. Resolution: 1. Go to IIS Management Console Start -> Administration Tools -> Internet Information Services (IIS) Manager 2. Expand your server in the left pane and go to Application Pools 3. Right click to select ‘Add Application Pool’  4. Create anew AppPool. I have named it ASP.NET v2.0 AppPool (32-bit) and selected .NET Framework v2.0.50727 because I intend to run my ASP.NET 3.5 application on it. 5. Now right click the newly created AppPool and select Advanced Settings 6. Change the property “Enable 32-Bit Applications” from False to True  7. Now select your actual web application from the left panel. Right click the web application, and go to Manage Application -> Advanced Settings  8. Change the Property “Application Pool” to your newly created AppPool.  And… the error is gone…

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  • Subterranean IL: Exception handling 2

    - by Simon Cooper
    Control flow in and around exception handlers is tightly controlled, due to the various ways the handler blocks can be executed. To start off with, I'll describe what SEH does when an exception is thrown. Handling exceptions When an exception is thrown, the CLR stops program execution at the throw statement and searches up the call stack looking for an appropriate handler; catch clauses are analyzed, and filter blocks are executed (I'll be looking at filter blocks in a later post). Then, when an appropriate catch or filter handler is found, the stack is unwound to that handler, executing successive finally and fault handlers in their own stack contexts along the way, and program execution continues at the start of the catch handler. Because catch, fault, finally and filter blocks can be executed essentially out of the blue by the SEH mechanism, without any reference to preceding instructions, you can't use arbitary branches in and out of exception handler blocks. Instead, you need to use specific instructions for control flow out of handler blocks: leave, endfinally/endfault, and endfilter. Exception handler control flow try blocks You cannot branch into or out of a try block or its handler using normal control flow instructions. The only way of entering a try block is by either falling through from preceding instructions, or by branching to the first instruction in the block. Once you are inside a try block, you can only leave it by throwing an exception or using the leave <label> instruction to jump to somewhere outside the block and its handler. The leave instructions signals the CLR to execute any finally handlers around the block. Most importantly, you cannot fall out of the block, and you cannot use a ret to return from the containing method (unlike in C#); you have to use leave to branch to a ret elsewhere in the method. As a side effect, leave empties the stack. catch blocks The only way of entering a catch block is if it is run by the SEH. At the start of the block execution, the thrown exception will be the only thing on the stack. The only way of leaving a catch block is to use throw, rethrow, or leave, in a similar way to try blocks. However, one thing you can do is use a leave to branch back to an arbitary place in the handler's try block! In other words, you can do this: .try { // ... newobj instance void [mscorlib]System.Exception::.ctor() throw MidTry: // ... leave.s RestOfMethod } catch [mscorlib]System.Exception { // ... leave.s MidTry } RestOfMethod: // ... As far as I know, this mechanism is not exposed in C# or VB. finally/fault blocks The only way of entering a finally or fault block is via the SEH, either as the result of a leave instruction in the corresponding try block, or as part of handling an exception. The only way to leave a finally or fault block is to use endfinally or endfault (both compile to the same binary representation), which continues execution after the finally/fault block, or, if the block was executed as part of handling an exception, signals that the SEH can continue walking the stack. filter blocks I'll be covering filters in a separate blog posts. They're quite different to the others, and have their own special semantics. Phew! Complicated stuff, but it's important to know if you're writing or outputting exception handlers in IL. Dealing with the C# compiler is probably best saved for the next post.

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  • RSA decrypting data in C# (.NET 3.5) which was encrypted with openssl in php 5.3.2

    - by panny
    Maybe someone can clear me up. I have been surfing on this a while now. Step #1: Create a root certificate Key generation on unix 1) openssl req -x509 -nodes -days 3650 -newkey rsa:1024 -keyout privatekey.pem -out mycert.pem 2) openssl rsa -in privatekey.pem -pubout -out publickey.pem 3) openssl pkcs12 -export -out mycertprivatekey.pfx -in mycert.pem -inkey privatekey.pem -name "my certificate" Step #2: Does root certificate work on php: YES PHP side I used the publickey.pem to read it into php: $publicKey = "file://C:/publickey.pem"; $privateKey = "file://C:/privatekey.pem"; $plaintext = "123"; openssl_public_encrypt($plaintext, $encrypted, $publicKey); $transfer = base64_encode($encrypted); openssl_private_decrypt($encrypted, $decrypted, $privateKey); echo $decrypted; // "123" OR $server_public_key = openssl_pkey_get_public(file_get_contents("C:\publickey.pem")); // rsa encrypt openssl_public_encrypt("123", $encrypted, $server_public_key); and the privatekey.pem to check if it works: openssl_private_decrypt($encrypted, $decrypted, openssl_get_privatekey(file_get_contents("C:\privatekey.pem"))); echo $decrypted; // "123" Coming to the conclusion, that encryption/decryption works fine on the php side with these openssl root certificate files. Step #3: Does root certificate work on .NET: YES C# side In same manner I read the keys into a .net C# console program: X509Certificate2 myCert2 = new X509Certificate2(); RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); try { myCert2 = new X509Certificate2(@"C:\mycertprivatekey.pfx"); rsa = (RSACryptoServiceProvider)myCert2.PrivateKey; } catch (Exception e) { } byte[] test = {Convert.ToByte("123")}; string t = Convert.ToString(rsa.Decrypt(rsa.Encrypt(test, false), false)); Coming to the point, that encryption/decryption works fine on the c# side with these openssl root certificate files. Step #4: Enrypt in php and Decrypt in .NET: !!NO!! PHP side $onett = "123" .... openssl_public_encrypt($onett, $encrypted, $server_public_key); $onettbase64 = base64_encode($encrypted); copy - paste $onettbase64 ("LkU2GOCy4lqwY4vtPI1JcsxgDgS2t05E6kYghuXjrQe7hSsYXETGdlhzEBlp+qhxzTXV3pw+AS5bEg9CPxqHus8fXHOnXYqsd2HL20QSaz+FjZee6Kvva0cGhWkFdWL+ANDSOWRWo/OMhm7JVqU3P/44c3dLA1eu2UsoDI26OMw=") into c# program: C# side byte[] transfered_onettbase64 = Convert.FromBase64String("LkU2GOCy4lqwY4vtPI1JcsxgDgS2t05E6kYghuXjrQe7hSsYXETGdlhzEBlp+qhxzTXV3pw+AS5bEg9CPxqHus8fXHOnXYqsd2HL20QSaz+FjZee6Kvva0cGhWkFdWL+ANDSOWRWo/OMhm7JVqU3P/44c3dLA1eu2UsoDI26OMw="); string k = Convert.ToString(rsa.Decrypt(transfered_onettbase64, false)); // Bad Data exception == Exception while decrypting!!! Any ideas?

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  • jQuery ajax() returning json object to another function on success causes error

    - by Michael Mao
    Hi all: I got stuck in this problem for an hour. I am thinking this is something relates to variable scoping ? Anyway, here is the code : function loadRoutes(from_city) { $.ajax( { url: './ajax/loadRoutes.php', async : true, cache : false, timeout : 10000, type : "POST", dataType: 'json', data : { "from_city" : from_city }, error : function(data) { console.log('error occured when trying to load routes'); }, success : function(data) { console.log('routes loaded successfully.'); $('#upperright').html(""); //reset upperright box to display nothing. return data; //this line ruins all //this section works just fine. $.each(data.feedback, function(i, route) { console.log("route no. :" + i + " to_city : " + route.to_city + " price :" + route.price); doSomethingHere(i); }); } }); } The for each section works just fine inside the success callback region. I can see Firebug console outputs the route ids with no problem at all. For decoupling purpose, I reckon it would be better to just return the data object, which in JSON format, to a variable in the caller function, like this: //ajax load function function findFromCity(continent, x, y) { console.log("clicked on " + continent + ' ' + x + ',' + y); $.ajax( { url: './ajax/findFromCity.php', async : true, cache : false, timeout : 10000, type : "POST", dataType : 'json', data : { "continent" : continent, "x" : x, "y" : y }, error : function(data) { console.log('error occured when trying to find the from city'); }, success : function(data) { var cityname = data.from_city; //only query database if cityname was found if(cityname != 'undefined' && cityname != 'nowhere') { console.log('from city found : ' + cityname); data = loadRoutes(cityname); console.log(data); } } }); } Then all of a sudden, everything stops working! Firebug console reports data object as "undefined"... hasn't that being assigned by the returning object from the method loadRoutes(cityname)? Sorry my overall knowledge on javascript is quite limited, so now I am just like a "copycat" to work on my code in an amateur way.

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  • PHP throws 'Allowed memory exhausted' errors while migrating data in Drupal.

    - by Stan
    I'm trying to setup a tiny sandbox on a local machine to play around with Drupal. I created a few CCK types; in order to create a few nodes I wrote the following script: chdir('C:\..\drupal'); require_once '.\includes\bootstrap.inc'; drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL); module_load_include('inc', 'node', 'node.pages'); $node = array('type' => 'my_type'); $link = mysql_connect(..); mysql_select_db('my_db'); $query_bldg = ' SELECT stuff FROM table LIMIT 10 '; $result = mysql_query($query_bldg); while ($row = mysql_fetch_object($result)) { $form_state = array(); $form_state['values']['name'] = 'admin'; $form_state['values']['status'] = 1; $form_state['values']['op'] = t('Save'); $form_state['values']['title'] = $row->val_a; $form_state['values']['my_field'][0]['value'] = $row->val_b; ## About another dozen or so of similar assignments... drupal_execute('node_form', $form_state, (object)$node); } Here are a few relevant lines from php_errors.log: [12-Jun-2010 05:02:47] PHP Notice: Undefined index: REMOTE_ADDR in C:\..\drupal\includes\bootstrap.inc on line 1299 [12-Jun-2010 05:02:47] PHP Notice: Undefined index: REMOTE_ADDR in C:\..\drupal\includes\bootstrap.inc on line 1299 [12-Jun-2010 05:02:47] PHP Warning: session_start(): Cannot send session cookie - headers already sent by (output started at C:\..\drupal\includes\bootstrap.inc:1299) in C:\..\drupal\includes\bootstrap.inc on line 1143 [12-Jun-2010 05:02:47] PHP Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at C:\..\drupal\includes\bootstrap.inc:1299) in C:\..\drupal\includes\bootstrap.inc on line 1143 [12-Jun-2010 05:02:47] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\..\drupal\includes\bootstrap.inc:1299) in C:\..\drupal\includes\bootstrap.inc on line 709 [12-Jun-2010 05:02:47] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\..\drupal\includes\bootstrap.inc:1299) in C:\..\drupal\includes\bootstrap.inc on line 710 [12-Jun-2010 05:02:47] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\..\drupal\includes\bootstrap.inc:1299) in C:\..\drupal\includes\bootstrap.inc on line 711 [12-Jun-2010 05:02:47] PHP Warning: Cannot modify header information - headers already sent by (output started at C:\..\drupal\includes\bootstrap.inc:1299) in C:\..\drupal\includes\bootstrap.inc on line 712 [12-Jun-2010 05:02:47] PHP Notice: Undefined index: REMOTE_ADDR in C:\..\drupal\includes\bootstrap.inc on line 1299 [12-Jun-2010 05:02:48] PHP Fatal error: Allowed memory size of 239075328 bytes exhau sted (tried to allocate 261904 bytes) in C:\..\drupal\includes\form.inc on line 488 [12-Jun-2010 05:03:22] PHP Fatal error: Allowed memory size of 239075328 bytes exhausted (tried to allocate 261904 bytes) in C:\..\drupal\includes\form.inc on line 488 [12-Jun-2010 05:04:34] PHP Fatal error: Allowed memory size of 262144 bytes exhausted (tried to allocate 261904 bytes) in Unknown on line 0 At this point any action php takes results in the last error shown above. I tried increasing the value of memory_limit in php.ini before the final Fatal error which obviously didn't help. How can the error be eliminated? Am I on a correct path to migrating data into Drupal or should the cck tables be operated on directly? Windows XP PHP 5.3.2 VC6 Apache 2.2

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