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  • How do I pass a lot of parameters to views in Django?

    - by Mark
    I'm very new to Django and I'm trying to build an application to present my data in tables and charts. Till now my learning process went very smooth, but now I'm a bit stuck. My pageview retrieves large amounts of data from a database and puts it in the context. The template then generates different html-tables. So far so good. Now I want to add different charts to the template. I manage to do this by defining <img src=".../> tags. The Matplotlib chart is generate in my chartview an returned via: response=HttpResponse(content_type='image/png') canvas.print_png(response) return response Now I have different questions: the data is retrieved twice from the database. Once in the pageview to render the tables, and again in the chartview for making the charts. What is the best way to pass the data, already in the context of the page to the chartview? I need a lot of charts, each with different datasets. I could make a chartview for each chart, but probably there is a better way. How do I pass the different dataset names to the chartview? Some charts have 20 datasets, so I don't think that passing these dataset parameters via the url (like: <imgm src="chart/dataset1/dataset2/.../dataset20/chart.png />) is the right way. Any advice?

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  • php cli script hangs with no messages

    - by julio
    Hi-- I've written a PHP script that runs via SSH and nohup, meant to process records from a database and do stuff with them (eg. process some images, update some rows). It works fine with small loads, up to maybe 10k records. I have some larger datasets that process around 40k records (not a lot, I realize, but it adds up to a lot of work when each record requires the download and processing of up to 50 images). The larger datasets can take days to process. Sometimes I'll see in my debug logs memory errors, which are clear enough-- but sometimes the script just appears to "die" or go zombie on me. My tail of the debug log just stops, with no error messages, the tail of the nohup log ends with no error, and the process is still showing in a ps list, looking like this-- 26075 pts/0 S 745:01 /usr/bin/php ./import.php but no work is getting done. Can anyone give me some ideas on why a process would just quit? The obvious things (like a php script timeout and memory issues) are not a factor, as far as I can tell. Thanks for any tips PS-- this is hosted on a godaddy VDS (not my choice). I am sort of suspecting that godaddy has some kind of limits that might kick in on me despite what overrides I put in the code (such as set_time_limit(0);).

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  • Apply a recursive CTE on grouped table rows (SQL server 2005).

    - by Evan V.
    Hi all, I have a table (ROOMUSAGE) containing the times people check in and out of rooms grouped by PERSONKEY and ROOMKEY. It looks like this: PERSONKEY | ROOMKEY | CHECKIN | CHECKOUT | ROW ---------------------------------------------------------------- 1 | 8 | 13-4-2010 10:00 | 13-4-2010 11:00 | 1 1 | 8 | 13-4-2010 08:00 | 13-4-2010 09:00 | 2 1 | 1 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 1 | 1 | 13-4-2010 14:00 | 13-4-2010 15:00 | 2 1 | 1 | 13-4-2010 13:00 | 13-4-2010 14:00 | 3 13 | 2 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 13 | 2 | 13-4-2010 15:00 | 13-4-2010 16:00 | 2 I want to select just the consecutive rows for each PERSONKEY, ROOMKEY grouping. So the desired resulting table is: PERSONKEY | ROOMKEY | CHECKIN | CHECKOUT | ROW ---------------------------------------------------------------- 1 | 8 | 13-4-2010 10:00 | 13-4-2010 11:00 | 1 1 | 1 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 1 | 1 | 13-4-2010 14:00 | 13-4-2010 15:00 | 2 1 | 1 | 13-4-2010 13:00 | 13-4-2010 14:00 | 3 13 | 2 | 13-4-2010 15:00 | 13-4-2010 16:00 | 1 I want to avoid using cursors so I thought I would use a recursive CTE. Here is what I came up with: ;with CTE (PERSONKEY, ROOMKEY, CHECKIN, CHECKOUT, ROW) as (select RU.PERSONKEY, RU.ROOMKEY, RU.CHECKIN, RU.CHECKOUT, RU.ROW from ROOMUSAGE RU where RU.ROW = 1 union all select RU.PERSONKEY, RU.ROOMKEY, RU.CHECKIN, RU.CHECKOUT, RU.ROW from ROOMUSAGE RU inner join CTE on RU.ROWNUM = CTE.ROWNUM + 1 where CTE.CHECKIN = RU.CHECKOUT and CTE.PERSONKEY = RU.PERSONKEY and CTE.ROOMKEY = RU.ROOMKEY) This worked OK for very small datasets (under 100 records) but it's unusable on large datasets. I'm thinking that I should somehow apply the cte recursevely on each PERSONKEY, ROOMKEY grouping on my ROOMUSAGE table but I am not sure how to do that. Any help would be much appreciated, Cheers!

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  • How do I pass a lot of parameters to views in Dango?

    - by Mark
    I'm very new to Django and I'm trying to build an application to present my data in tables and charts. Till now my learning process went very smooth, but now I'm a bit stuck. My pageview retrieves large amounts of data from a database and puts it in the context. The template then generates different html-tables. So far so good. Now I want to add different charts to the template. I manage to do this by defining <img src=".../> tags. The Matplotlib chart is generate in my chartview an returned via: response=HttpResponse(content_type='image/png') canvas.print_png(response) return response Now I have different questions: the data is retrieved twice from the database. Once in the pageview to render the tables, and again in the chartview for making the charts. What is the best way to pass the data, already in the context of the page to the chartview? I need a lot of charts, each with different datasets. I could make a chartview for each chart, but probably there is a better way. How do I pass the different dataset names to the chartview? Some charts have 20 datasets, so I don't think that passing these dataset parameters via the url (like: <imgm src="chart/dataset1/dataset2/.../dataset20/chart.png />) is the right way. Any advice?

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  • L10N: Trusted test data for Locale Specific Sorting

    - by Chris Betti
    I'm working on an internationalized database application that supports multiple locales in a single instance. When international users sort data in the applications built on top of the database, the database theoretically sorts the data using a collation appropriate to the locale associated with the data the user is viewing. I'm trying to find sorted lists of words that meet two criteria: the sorted order follows the collation rules for the locale the words listed will allow me to exercise most / all of the specific collation rules for the locale I'm having trouble finding such trusted test data. Are such sort-testing datasets currently available, and if so, what / where are they? "words.en.txt" is an example text file containing American English text: Andrew Brian Chris Zachary I am planning on loading the list of words into my database in randomized order, and checking to see if sorting the list conforms to the original input. Because I am not fluent in any language other than English, I do not know how to create sample datasets like the following sample one in French (call it "words.fr.txt"): cote côte coté côté The French prefer diacritical marks to be ordered right to left. If you sorted that using code-point order, it likely comes out like this (which is an incorrect collation): cote coté côte côté Thank you for the help, Chris

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  • Generic dataset handling library

    - by Pep.
    Hello, I want to build a generic Perl module for handling and analysing biomedical character separated datasets and which can, most certain, be used on any kind of datasets that contain a mixture of categorical (A,B,C,..) and continuous (1.2,3,881..) and identifier (XXX1,XXX2...). The plan is to have people initialize the module and then use some arguments to point to the data file(s), the place were the analysis reports should be placed and the structure of the data. By structure of data I mean which variable is in which place and its name/type. And this is where I need some enlightenment. I am baffled how to do this in a clean way. Obviously, having people create a simple schema file, be it XML or some other format would be the cleanest but maybe not all people enjoy doing something like this. The solutions I can think of are: Create a configuration file in XML or similar and with a prespecified format. Pass the information during initialization of the module. Use the first row of the data as headers and try to guess types (ouch) Surely there must be a "canonical" way of doing this that is also usable and efficient. Thanks p.

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  • How can I build a generic dataset-handling Perl library?

    - by Pep.
    Hello, I want to build a generic Perl module for handling and analysing biomedical character separated datasets and which can, most certain, be used on any kind of datasets that contain a mixture of categorical (A,B,C,..) and continuous (1.2,3,881..) and identifier (XXX1,XXX2...). The plan is to have people initialize the module and then use some arguments to point to the data file(s), the place were the analysis reports should be placed and the structure of the data. By structure of data I mean which variable is in which place and its name/type. And this is where I need some enlightenment. I am baffled how to do this in a clean way. Obviously, having people create a simple schema file, be it XML or some other format would be the cleanest but maybe not all people enjoy doing something like this. The solutions I can think of are: Create a configuration file in XML or similar and with a prespecified format. Pass the information during initialization of the module. Use the first row of the data as headers and try to guess types (ouch) Surely there must be a "canonical" way of doing this that is also usable and efficient. Thanks p.

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  • Open World Day 1 Continued

    - by Antony Reynolds
    A Day in the Life of an Oracle OpenWorld Attendee Part II A couple of things I forgot to mention about yesterdays OpenWorld. First I attended a presentation on SOA Suite and Virtualization which explained how Oracle Virtual Assembly Builder (OVAB) can be used to accelerate the deployment of an Enterprise Deployment Guide (EDG) compliant SOA Suite infrastructure.  OVAB provides the ability to introspect a deployed software component such as WebLogic Server, SOA Suite or other components and extract the configuration and package it up for rapid deployment into an Oracle Virtual Machine.  OVAB allows multiple machines to be configured and connections made between the machines and outside resources such as databases.  That by itself is pretty cool and has been available for a while in OVAB.  What is new is that Oracle has done this for an EDG compliant installations and made it available as an OVAB assembly for customers to use, significantly accelerating the deployment of an EDG deployment.  A real help for customers standing up EDG environments, particularly in test, dev and QA environments. The other thing I forgot to mention was the most memorable demo I saw at OpenWorld.  This was done by my co-author Matt Wright who was showcasing the products of his company Rubicon Red.  They showed a really cool application called OneSpot which puts all the information about a single users business processes in one spot!  Apparently a customer suggested the name.  It allows business flows to be defined that map onto events.  As events occur the status of the business flow is updated to reflect the change.  The interface is strongly reminiscent of social media sites and provides a graphical view of business flows.  So how does this differ from BPEL and BPM process flows?  The OneSpot process flow is more like a BAM process flow, it is based on events arriving from multiple sources, and is focused on the clients view of the process, not the actual business process.  This is important because it allows an end user to get a view of where his current business flow is and what actions, if any, are required of him.  This by itself is great, but better still is that OneSpot has a real time updating view of events that have occurred (BAM style no need to refresh the browser).  This means that as new events occur the end user can see them and jump to the business flow or take other appropriate actions.  Under the covers OneSpot makes use of Oracle Human Workflow to provide a forms interface, but this is not the HWF GUI you know!  The HWF GUI screens are much prettier and have more of a social media feel about them due to their use of images and pulling in relevant related information.  If you are at OOW I strongly recommend you visit Matt or John at the Rubicon Red stand and ask, no demand a demo of OneSpot!

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  • APPLY LATE BINDING IN .NET 4.0 AND DIFFERENTIATE IT WITH VAR KEYWORD

    Latebinding is a common term among VB6.0 programmers. C# was always strongly typed. But in 3.x version they introducded var keyword which suporting dynamic binding. But not late binding. After 4.0 relese they came up with dynamic keyword. This fully supporting late binding. Below explaining the difference between var and dynamics. Also a simple example saying where we can use dynamics in C#

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  • The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume

    - by Jason Fitzpatrick
    Last week we showed you how to set up a simple, but strongly encrypted, TrueCrypt volume to help you protect your sensitive data. This week we’re digging in deeper and showing you how to hide your encrypted data within your encrypted data. The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage Reader Request: How To Repair Blurry Photos

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  • New Slides - and a discussion about Dictionary Statistics

    - by Mike Dietrich
    First of all we have just upoaded a new version of the Upgrade and Migration Workshop slides with some added information. So please feel free to download them from here.The slides have one new interesting information which lead to a discussion I've had in the past days with a very large customer regarding their upgrades - and internally on the mailing list targeting an EBS database upgrade from Oracle 10.2 to Oracle 11.2. Why are we creating dictionary statistics during upgrade? I'd believe this forced dictionary statistics creation got introduced with the desupport of the Rule Based Optimizer in Oracle 10g. The goal: as RBO is not supported anymore we have to make sure that the data dictionary has fresh and non-stale statistics. Actually that would have led in Oracle 9i to strange behaviour in some databases - so in Oracle 9i this was strongly disrecommended. The upgrade scripts got hardcoded to create these stats. But during tests we had the following findings: It's important to create dictionary statistics the night before the upgrade. Not two weeks before, not 60 minutes before your downtime begins. But very close to the upgrade. From Oracle 10g onwards you'd just say: $ execute DBMS_STATS.GATHER_DICTIONARY_STATS; This is important to make sure you have fresh dictionary statistics during upgrade for performance reasons. Tests have shown that running an upgrade without valid dictionary statistics might slow down the whole upgrade by factors of 2x-3x. And it would be also a great idea post upgrade to create again fresh dictionary statistics when you've did suppress the stats creation during the upgrade process. Suppress? Yes, you could set this underscore parameter in the init.ora: _optim_dict_stats_at_db_cr_upg=FALSE to suppress the forced dictionary statistics collection during an upgrade. We believe strongly that (a) people using the default statistics creation process which will create dictionary statistics by default and (b) create fresh stats before upgrade on the dictionary. Therefore we find it save once you have followed our advice to use the underscore during upgrade. And we've taken out that forced statistics collection during upgrade in the next release of the database. Please note: If you are using the DBUA for the upgrade it will remove underscore parameters for the upgrade run to improve performance - which is generally a good idea. So you'll have to start the DBUA with that call: $ dbua -initParam "_optim_dict_stats_at_cb_cr_upg"=FALSE -Mike

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  • Four New Videos on ASP.NET MVC 2

    Microsoft?s Jon Galloway has recorded 4 new ?quick hit? videos to help you get up to speed on new features in ASP.NET MVC 2. Learn about HTML Encoding, Strongly Typed Helpers, Model Validation, and Template Customization in these newest videos.

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  • Get to Know a Candidate (2 of 25): Merlin Miller&ndash;American Third Position Party

    - by Brian Lanham
    DISCLAIMER: This is not a post about “Romney” or “Obama”. This is not a post for whom I am voting. Information sourced for Wikipedia. Meet Merlin Miller of American Third Position Party In addition to being American Third Position Party nominee, Miller is an independent film maker.  He is a graduate of West Point and has commanded two units in the United States Army.  After military service he worked as an industrial engineering manager for Michelin Tire.  He learned about film making by earning an MFA from the University of Southern California. Mr. Miller is on the ballot in: CO, NJ, and TN. In the 2000’s, Miller began taking an increasingly paleoconservative political stance.  He claimed that Hollywood “ surreptitiously seeks to destroy our European-American heritage and our Christian-based traditional values, and replace them with values that debase these traditional values and elevate minorities as paragons of virtue and wisdom....Today’s motion pictures, in concert with other forms of mass media entertainment, are the greatest enemies to the well-being of our progeny and the future of our country.” Miller states that he "doesn't like" interracial marriage; however, he does not support outlawing interracial marriage, either.  Miller has denied being anti-Semitic, instead claiming that he merely opposes "favoritism" granted to Jews in the film industry.  He also opposes illegal immigration and what he refers to as "wide open borders" in the United States. The American Third Position Party (A3P) is a third positionist American political party which promotes white supremacy.  It was officially launched in January 2010 (although in November 2009 it filed papers to get on a ballot in California) partially to channel the right-wing populist resentment engendered by the financial crisis of 2007–2010 and the policies of the Obama administration and defines its principal mission as representing the political interests of white Americans. The party takes a strong stand against immigration and globalization, and strongly supports an anti-interventionist foreign policy. Although the party does not support labor unions, they do strongly support the labor rights of the American working class on a platform of placing American workers first over illegal immigrant workers and banning of overseas corporate relocation of American industry and technology Third Position or Third Alternative refers to a revolutionary nationalist political position that emphasizes its opposition to both communism and capitalism. Advocates of Third Position politics typically present themselves as "beyond left and right", instead claiming to syncretize radical ideas from both ends of the political spectrum Learn more about Merlin Miller and American Third Position Party on Wikipedia.

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  • Four New Videos on ASP.NET MVC 2

    Microsoft’s Jon Galloway has recorded 4 new “quick hit” videos to help you get up to speed on new features in ASP.NET MVC 2. Learn about HTML Encoding, Strongly Typed Helpers, Model Validation, and Template Customization in these newest videos.

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  • NetBeans IDE 7.3 Knows Null

    - by Geertjan
    What's the difference between these two methods, "test1" and "test2"? public int test1(String str) {     return str.length(); } public int test2(String str) {     if (str == null) {         System.err.println("Passed null!.");         //forgotten return;     }     return str.length(); } The difference, or at least, the difference that is relevant for this blog entry, is that whoever wrote "test2" apparently thinks that the variable "str" may be null, though did not provide a null check. In NetBeans IDE 7.3, you see this hint for "test2", but no hint for "test1", since in that case we don't know anything about the developer's intention for the variable and providing a hint in that case would flood the source code with too many false positives:  Annotations are supported in understanding how a piece of code is intended to be used. If method return types use @Nullable, @NullAllowed, @CheckForNull, the value is considered to be "strongly possible to be null", as well as if the variable is tested to be null, as shown above. When using @NotNull, @NonNull, @Nonnull, the value is considered to be non-null. (The exact FQNs of the annotations are ignored, only simple names are checked.) Here are examples showing where the hints are displayed for the non-null hints (the "strongly possible to be null" hints are not shown below, though you can see one of them in the screenshot above), together with a comment showing what is shown when you hover over the hint: There isn't a "one size fits all" refactoring for these various instances relating to null checks, hence you can't do an automated refactoring across your code base via tools in NetBeans IDE, as shown yesterday for class member reordering across code bases. However, you can, instead, go to Source | Inspect and then do a scan throughout a scope (e.g., current file/package/project or combinations of these or all open projects) for class elements that the IDE identifies as potentially having a problem in this area: Thanks to Jan Lahoda, who reports that this currently also works in NetBeans IDE 7.3 dev builds for fields but that may need to be disabled since right now too many false positives are returned, for help with the info above and any misunderstandings are my own fault!

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  • Statistics for and Details About Open Source Swing Projects

    - by user592704
    I'm looking for process-relative information on open-source Swing projects: how the task was described how many developers were involved how much time the solution was taken etc. Are there any open source (online) chronicles in that direction? I strongly prefer projects that include the authors' names. I watched this project and it seems fine but still I couldn't find any information concerning some current project task(s), its developers group, some chronicles (tips, milestones, feedbacks etc) For example if I see this swing component I'd like to know the above information.

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  • ASP.NET Querystring: Basic Dynamic URL Formations

    If you are a beginner to ASP.NET 3.5 you might ask How are dynamic URLs using queries generated in ASP.NET In developing dynamic websites those that strongly depend on using a database to present content it is of the utmost importance that you clearly understand how to work with query-based URLs. This article will show you how.... Reach Millions of Netbook Users Easily create and sell netbook apps with the Intel? Atom? Developer program

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  • Image captions and wrapping [migrated]

    - by Charles
    What's the best way to add a caption below an image? The image and its caption will be floated right, and the text on the caption needs to wrap -- a 200x200px image shouldn't have a caption of width 800px. I would strongly prefer a solution that allows me to update images (with different widths) without changing the CSS or markup. For reasons beyond my control the image itself will also be floated right, but this should not be too problematic.

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  • Inconsistent results in R with RNetCDF - why?

    - by sarcozona
    I am having trouble extracting data from NetCDF data files using RNetCDF. The data files each have 3 dimensions (longitude, latitude, and a date) and 3 variables (latitude, longitude, and a climate variable). There are four datasets, each with a different climate variable. Here is some of the output from print.nc(p8m.tmax) for clarity. The other datasets are identical except for the specific climate variable. dimensions: month = UNLIMITED ; // (1368 currently) lat = 3105 ; lon = 7025 ; variables: float lat(lat) ; lat:long_name = "latitude" ; lat:standard_name = "latitude" ; lat:units = "degrees_north" ; float lon(lon) ; lon:long_name = "longitude" ; lon:standard_name = "longitude" ; lon:units = "degrees_east" ; short tmax(lon, lat, month) ; tmax:missing_value = -9999 ; tmax:_FillValue = -9999 ; tmax:units = "degree_celsius" ; tmax:scale_factor = 0.01 ; tmax:valid_min = -5000 ; tmax:valid_max = 6000 ; I am getting behavior I don't understand when I use the var.get.nc function from the RNetCDF package. For example, when I attempt to extract 82 values beginning at stval from the maximum temperature data (p8m.tmax <- open.nc(tmaxdataset.nc)) with > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,82)) (where lon_val and lat_val specify the location in the dataset of the coordinates I'm interested in and stval is stval is set to which(time_vec==200201), which in this case equaled 1285.) I get Error: Invalid argument But after successfully extracting 80 and 81 values > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,80)) > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,81)) the command with 82 works: > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,82)) [1] 444 866 1063 ... [output snipped] The same problem occurs in the identically structured tmin file, but at 36 instead of 82: > var.get.nc(p8m.tmin,'tmin', start=c(lon_val, lat_val, stval),count=c(1,1,36)) produces Error: Invalid argument But after repeating with counts of 30, 31, etc > var.get.nc(p8m.tmin,'tmin', start=c(lon_val, lat_val, stval), count=c(1,1,36)) works. These examples make it seem like the function is failing at the last count, but that actually isn't the case. In the first example, var.get.nc gave Error: Invalid argument after I asked for 84 values. I then narrowed the failure down to the 82nd count by varying the starting point in the dataset and asking for only 1 value at a time. The particular number the problem occurs at also varies. I can close and reopen the dataset and have the problem occur at a different location. In the particular examples above, lon_val and lat_val are 1595 and 1751, respectively, identifying the location in the dataset along the lat and lon dimensions for the latitude and longitude I'm interested in. The 1595th latitude and 1751th longitude are not the problem, however. The problem occurs with all other latitude and longitudes I've tried. Varying the starting location in the dataset along the climate variable dimension (stval) and/or specifying it different (as a number in the command instead of the object stval) also does not fix the problem. This problem doesn't always occur. I can run identical code three times in a row (clearing all objects in between runs) and get a different outcome each time. The first run may choke on the 7th entry I'm trying to get, the second might work fine, and the third run might choke on the 83rd entry. I'm absolutely baffled by such inconsistent behavior. The open.nc function has also started to fail with the same Error: Invalid argument. Like the var.get.nc problems, it also occurs inconsistently. Does anyone know what causes the initial failure to extract the variable? And how I might prevent it? Could have to do with the size of the data files (~60GB each) and/or the fact that I'm accessing them through networked drives? This was also asked here: https://stat.ethz.ch/pipermail/r-help/2011-June/281233.html > sessionInfo() R version 2.13.0 (2011-04-13) Platform: i386-pc-mingw32/i386 (32-bit) locale: [1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C [5] LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] reshape_0.8.4 plyr_1.5.2 RNetCDF_1.5.2-2 loaded via a namespace (and not attached): [1] tools_2.13.0

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  • Passing multiple POST parameters to Web API Controller Methods

    - by Rick Strahl
    ASP.NET Web API introduces a new API for creating REST APIs and making AJAX callbacks to the server. This new API provides a host of new great functionality that unifies many of the features of many of the various AJAX/REST APIs that Microsoft created before it - ASP.NET AJAX, WCF REST specifically - and combines them into a whole more consistent API. Web API addresses many of the concerns that developers had with these older APIs, namely that it was very difficult to build consistent REST style resource APIs easily. While Web API provides many new features and makes many scenarios much easier, a lot of the focus has been on making it easier to build REST compliant APIs that are focused on resource based solutions and HTTP verbs. But  RPC style calls that are common with AJAX callbacks in Web applications, have gotten a lot less focus and there are a few scenarios that are not that obvious, especially if you're expecting Web API to provide functionality similar to ASP.NET AJAX style AJAX callbacks. RPC vs. 'Proper' REST RPC style HTTP calls mimic calling a method with parameters and returning a result. Rather than mapping explicit server side resources or 'nouns' RPC calls tend simply map a server side operation, passing in parameters and receiving a typed result where parameters and result values are marshaled over HTTP. Typically RPC calls - like SOAP calls - tend to always be POST operations rather than following HTTP conventions and using the GET/POST/PUT/DELETE etc. verbs to implicitly determine what operation needs to be fired. RPC might not be considered 'cool' anymore, but for typical private AJAX backend operations of a Web site I'd wager that a large percentage of use cases of Web API will fall towards RPC style calls rather than 'proper' REST style APIs. Web applications that have needs for things like live validation against data, filling data based on user inputs, handling small UI updates often don't lend themselves very well to limited HTTP verb usage. It might not be what the cool kids do, but I don't see RPC calls getting replaced by proper REST APIs any time soon.  Proper REST has its place - for 'real' API scenarios that manage and publish/share resources, but for more transactional operations RPC seems a better choice and much easier to implement than trying to shoehorn a boatload of endpoint methods into a few HTTP verbs. In any case Web API does a good job of providing both RPC abstraction as well as the HTTP Verb/REST abstraction. RPC works well out of the box, but there are some differences especially if you're coming from ASP.NET AJAX service or WCF Rest when it comes to multiple parameters. Action Routing for RPC Style Calls If you've looked at Web API demos you've probably seen a bunch of examples of how to create HTTP Verb based routing endpoints. Verb based routing essentially maps a controller and then uses HTTP verbs to map the methods that are called in response to HTTP requests. This works great for resource APIs but doesn't work so well when you have many operational methods in a single controller. HTTP Verb routing is limited to the few HTTP verbs available (plus separate method signatures) and - worse than that - you can't easily extend the controller with custom routes or action routing beyond that. Thankfully Web API also supports Action based routing which allows you create RPC style endpoints fairly easily:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumApi", action = "GetAblums" } ); This uses traditional MVC style {action} method routing which is different from the HTTP verb based routing you might have read a bunch about in conjunction with Web API. Action based routing like above lets you specify an end point method in a Web API controller either via the {action} parameter in the route string or via a default value for custom routes. Using routing you can pass multiple parameters either on the route itself or pass parameters on the query string, via ModelBinding or content value binding. For most common scenarios this actually works very well. As long as you are passing either a single complex type via a POST operation, or multiple simple types via query string or POST buffer, there's no issue. But if you need to pass multiple parameters as was easily done with WCF REST or ASP.NET AJAX things are not so obvious. Web API has no issue allowing for single parameter like this:[HttpPost] public string PostAlbum(Album album) { return String.Format("{0} {1:d}", album.AlbumName, album.Entered); } There are actually two ways to call this endpoint: albums/PostAlbum Using the Model Binder with plain POST values In this mechanism you're sending plain urlencoded POST values to the server which the ModelBinder then maps the parameter. Each property value is matched to each matching POST value. This works similar to the way that MVC's  ModelBinder works. Here's how you can POST using the ModelBinder and jQuery:$.ajax( { url: "albums/PostAlbum", type: "POST", data: { AlbumName: "Dirty Deeds", Entered: "5/1/2012" }, success: function (result) { alert(result); }, error: function (xhr, status, p3, p4) { var err = "Error " + " " + status + " " + p3; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); Here's what the POST data looks like for this request: The model binder and it's straight form based POST mechanism is great for posting data directly from HTML pages to model objects. It avoids having to do manual conversions for many operations and is a great boon for AJAX callback requests. Using Web API JSON Formatter The other option is to post data using a JSON string. The process for this is similar except that you create a JavaScript object and serialize it to JSON first.album = { AlbumName: "PowerAge", Entered: new Date(1977,0,1) } $.ajax( { url: "albums/PostAlbum", type: "POST", contentType: "application/json", data: JSON.stringify(album), success: function (result) { alert(result); } }); Here the data is sent using a JSON object rather than form data and the data is JSON encoded over the wire. The trace reveals that the data is sent using plain JSON (Source above), which is a little more efficient since there's no UrlEncoding that occurs. BTW, notice that WebAPI automatically deals with the date. I provided the date as a plain string, rather than a JavaScript date value and the Formatter and ModelBinder both automatically map the date propertly to the Entered DateTime property of the Album object. Passing multiple Parameters to a Web API Controller Single parameters work fine in either of these RPC scenarios and that's to be expected. ModelBinding always works against a single object because it maps a model. But what happens when you want to pass multiple parameters? Consider an API Controller method that has a signature like the following:[HttpPost] public string PostAlbum(Album album, string userToken) Here I'm asking to pass two objects to an RPC method. Is that possible? This used to be fairly straight forward either with WCF REST and ASP.NET AJAX ASMX services, but as far as I can tell this is not directly possible using a POST operation with WebAPI. There a few workarounds that you can use to make this work: Use both POST *and* QueryString Parameters in Conjunction If you have both complex and simple parameters, you can pass simple parameters on the query string. The above would actually work with: /album/PostAlbum?userToken=sekkritt but that's not always possible. In this example it might not be a good idea to pass a user token on the query string though. It also won't work if you need to pass multiple complex objects, since query string values do not support complex type mapping. They only work with simple types. Use a single Object that wraps the two Parameters If you go by service based architecture guidelines every service method should always pass and return a single value only. The input should wrap potentially multiple input parameters and the output should convey status as well as provide the result value. You typically have a xxxRequest and a xxxResponse class that wraps the inputs and outputs. Here's what this method might look like:public PostAlbumResponse PostAlbum(PostAlbumRequest request) { var album = request.Album; var userToken = request.UserToken; return new PostAlbumResponse() { IsSuccess = true, Result = String.Format("{0} {1:d} {2}", album.AlbumName, album.Entered,userToken) }; } with these support types:public class PostAlbumRequest { public Album Album { get; set; } public User User { get; set; } public string UserToken { get; set; } } public class PostAlbumResponse { public string Result { get; set; } public bool IsSuccess { get; set; } public string ErrorMessage { get; set; } }   To call this method you now have to assemble these objects on the client and send it up as JSON:var album = { AlbumName: "PowerAge", Entered: "1/1/1977" } var user = { Name: "Rick" } var userToken = "sekkritt"; $.ajax( { url: "samples/PostAlbum", type: "POST", contentType: "application/json", data: JSON.stringify({ Album: album, User: user, UserToken: userToken }), success: function (result) { alert(result.Result); } }); I assemble the individual types first and then combine them in the data: property of the $.ajax() call into the actual object passed to the server, that mimics the structure of PostAlbumRequest server class that has Album, User and UserToken properties. This works well enough but it gets tedious if you have to create Request and Response types for each method signature. If you have common parameters that are always passed (like you always pass an album or usertoken) you might be able to abstract this to use a single object that gets reused for all methods, but this gets confusing too: Overload a single 'parameter' too much and it becomes a nightmare to decipher what your method actual can use. Use JObject to parse multiple Property Values out of an Object If you recall, ASP.NET AJAX and WCF REST used a 'wrapper' object to make default AJAX calls. Rather than directly calling a service you always passed an object which contained properties for each parameter: { parm1: Value, parm2: Value2 } WCF REST/ASP.NET AJAX would then parse this top level property values and map them to the parameters of the endpoint method. This automatic type wrapping functionality is no longer available directly in Web API, but since Web API now uses JSON.NET for it's JSON serializer you can actually simulate that behavior with a little extra code. You can use the JObject class to receive a dynamic JSON result and then using the dynamic cast of JObject to walk through the child objects and even parse them into strongly typed objects. Here's how to do this on the API Controller end:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } This is clearly not as nice as having the parameters passed directly, but it works to allow you to pass multiple parameters and access them using Web API. JObject is JSON.NET's generic object container which sports a nice dynamic interface that allows you to walk through the object's properties using standard 'dot' object syntax. All you have to do is cast the object to dynamic to get access to the property interface of the JSON type. Additionally JObject also allows you to parse JObject instances into strongly typed objects, which enables us here to retrieve the two objects passed as parameters from this jquery code:var album = { AlbumName: "PowerAge", Entered: "1/1/1977" } var user = { Name: "Rick" } var userToken = "sekkritt"; $.ajax( { url: "samples/PostAlbum", type: "POST", contentType: "application/json", data: JSON.stringify({ Album: album, User: user, UserToken: userToken }), success: function (result) { alert(result); } }); Summary ASP.NET Web API brings many new features and many advantages over the older Microsoft AJAX and REST APIs, but realize that some things like passing multiple strongly typed object parameters will work a bit differently. It's not insurmountable, but just knowing what options are available to simulate this behavior is good to know. Now let me say here that it's probably not a good practice to pass a bunch of parameters to an API call. Ideally APIs should be closely factored to accept single parameters or a single content parameter at least along with some identifier parameters that can be passed on the querystring. But saying that doesn't mean that occasionally you don't run into a situation where you have the need to pass several objects to the server and all three of the options I mentioned might have merit in different situations. For now I'm sure the question of how to pass multiple parameters will come up quite a bit from people migrating WCF REST or ASP.NET AJAX code to Web API. At least there are options available to make it work.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Creating Item Templates as Visual Studio 2010 Extensions

    - by maziar
    Technorati Tags: Visual Studio 2010 Extension,T4 Template,VSIX,Item Template Wizard This blog post briefly introduces creation of an item template as a Visual studio 2010 extension. Problem specification Assume you are writing a Framework for data-oriented applications and you decide to include all your application messages in a SQL server database table. After creating the table, your create a class in your framework for getting messages with a string key specified.   var message = FrameworkMessages.Get("ChangesSavedSuccess");   Everyone would say this code is so error prone, because message keys are not strong-typed, and might create errors in application that are not caught in tests. So we think of a way to make it strong-typed, i.e. create a class to use it like this:   var message = Messages.ChangesSavedSuccess; in Messages class the code looks like this: public string ChangesSavedSuccess {     get { return FrameworkMessages.Get("ChangesSavedSuccess"); } }   And clearly, we are not going to create the Messages class manually; we need a class generator for it.   Again assume that the application(s) that intend to use our framework, contain multiple sub-systems. So each sub-system need to have it’s own strong-typed message class that call FrameworkMessages.Get method. So we would like to make our code generator an Item Template so that each developer would easily add the item to his project and no other works would be necessary.   Solution We create a T4 Text Template to generate our strong typed class from database. Then create a Visual Studio Item Template with this generator and publish it.   What Are T4 Templates You might be already familiar with T4 templates. If it’s so, you can skip this section. T4 Text Template is a fine Visual Studio file type (.tt) that generates output text. This file is a mixture of text blocks and code logic (in C# or VB). For example, you can generate HTML files, C# classes, Resource files and etc with use of a T4 template.   Syntax highlighting In Visual Studio 2010 a T4 Template by default will no be syntax highlighted and no auto-complete is supported for it. But there is a fine visual studio extension named ‘Visual T4’ which can be downloaded free from VisualStudioGallery. This tool offers IntelliSense, syntax coloring, validation, transformation preview and more for T4 templates.     How Item Templates work in Visual Studio Visual studio extensions allow us to add some functionalities to visual studio. In our case we need to create a .vsix file that adds a template to visual studio item templates. Item templates are zip files containing the template file and a meta-data file with .vstemplate extension. This .vstemplate file is an XML file that provides some information about the template. A .vsix file also is a zip file (renamed to .vsix) that are open with visual studio extension installer. (Re-installing a vsix file requires that old one to be uninstalled from VS: Tools > Extension Manager.) Installing a vsix will need Visual Studio to be closed and re-opened to take effect. Visual studio extension installer will easily find the item template’s zip file and copy it to visual studio’s template items folder. You can find other visual studio templates in [<VS Install Path>\Common7\IDE\ItemTemplates] and you can edit them; but be very careful with VS default templates.   How Can I Create a VSIX file 1. Visual Studio SDK depending on your Visual Studio’s version, you need to download Microsoft Visual Studio SDK. Note that if you have VS 2010 SP1, you will need to download and install VS 2010 SP1 SDK; VS 2010 SDK will not be installed (unless you change registry value that indicated your service pack number). Here is the link for VS 2010 SP1 SDK. After downloading, Run it and follow the wizard to complete the installation.   2. Create the file you want to make it an Item Template Create a project (or use an existing one) and add you file, edit it to make it work fine.   Back to our own problem, we need to create a T4 (.tt) template. VS-Prok: Add > New Item > General > Text Template Type a file name, ex. Message.tt, and press Add. Create the T4 template file (in this blog I do not intend to include T4 syntaxes so I just write down the code which is clear enough for you to understand)   <#@ template debug="false" hostspecific="true" language="C#" #> <#@ output extension=".cs" #> <#@ Assembly Name="System.Data" #> <#@ Import Namespace="System.Data.SqlClient" #> <#@ Import Namespace="System.Text" #> <#@ Import Namespace="System.IO" #> <#     var connectionString = "server=Maziar-PC; Database=MyDatabase; Integrated Security=True";     var systemName = "Sys1";     var builder = new StringBuilder();     using (var connection = new SqlConnection(connectionString))     {         connection.Open();         var command = connection.CreateCommand();         command.CommandText = string.Format("SELECT [Key] FROM [Message] WHERE System = '{0}'", systemName);         var reader = command.ExecuteReader();         while (reader.Read())         {             builder.AppendFormat("        public static string {0} {{ get {{ return FrameworkMessages.Get(\"{0}\"); }} }}\r\n", reader[0]);         }     } #> namespace <#= System.Runtime.Remoting.Messaging.CallContext.LogicalGetData("NamespaceHint") #> {     public static class <#= Path.GetFileNameWithoutExtension(Host.TemplateFile) #>     { <#= builder.ToString() #>     } } As you can see the T4 template connects to a database, reads message keys and generates a class. Here is the output: namespace MyProject.MyFolder {     public static class Messages     {         public static string ChangesSavedSuccess { get { return FrameworkMessages.Get("ChangesSavedSuccess"); } }         public static string ErrorSavingChanges { get { return FrameworkMessages.Get("ErrorSavingChanges"); } }     } }   The output looks fine but there is one problem. The connectionString and systemName are hard coded. so how can I create an flexible item template? One of features of item templates in visual studio is that you can create a designer wizard for your item template, so I can get connection information and system name there. now lets go on creating the vsix file.   3. Create Template In visual studio click on File > Export Template a wizard will show up. if first step click on Item Template on in the combo box select the project that contains Messages.tt. click next. Select Messages.tt from list in second step. click next. In the third step, you should choose References. For this template, System and System.Data are needed so choose them. click next. write down template name, description, if you like add a .ico file as the icon file and also preview image. Uncheck automatically add the templare … . Copy the output location in clip board. click finish.     4. Create VSIX Project In VS, Click File > New > Project > Extensibility > VSIX Project Type a name, ex. FrameworkMessages, Location, etc. The project will include a .vsixmanifest file. Fill in fields like Author, Product Name, Description, etc.   In Content section, click on Add Content. choose content type as Item Template. choose source as file. remember you have the template file address in clipboard? now paste it in front of file. click OK.     5. Build VSIX Project That’s it, build the project and go to output directory. You see a .vsix file. you can run it now. After restarting VS, if you click on a project > Add > New Item, you will see your item in list and you can add it. When you add this item to a project, if it has not references to System and System.Data they will be added. but the problem mentioned in step 2 is seen now.     6. Create Design Wizard for your Item Template Create a project i.e. Windows Application named ‘Framework.Messages.Design’, but better change its output type to Class Library. Add References to Microsoft.VisualStudio.TemplateWizardInterface and envdte Add a class Named MessagesDesigner in your project and Implement IWizard interface in it. This is what you should write: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.VisualStudio.TemplateWizard; using EnvDTE; namespace Framework.Messages.Design {     class MessageDesigner : IWizard     {         private bool CanAddProjectItem;         public void RunStarted(object automationObject, Dictionary<string, string> replacementsDictionary, WizardRunKind runKind, object[] customParams)         {             // Prompt user for Connection String and System Name in a Windows form (ShowDialog) here             // (try to provide good interface)             // if user clicks on cancel of your windows form return;             string connectionString = "connection;string"; // Set value from the form             string systemName = "system;name"; // Set value from the form             CanAddProjectItem = true;             replacementsDictionary.Add("$connectionString$", connectionString);             replacementsDictionary.Add("$systemName$", systemName);         }         public bool ShouldAddProjectItem(string filePath)         {             return CanAddProjectItem;         }         public void BeforeOpeningFile(ProjectItem projectItem)         {         }         public void ProjectFinishedGenerating(Project project)         {         }         public void ProjectItemFinishedGenerating(ProjectItem projectItem)         {         }         public void RunFinished()         {         }     } }   before your code runs  replacementsDictionary contains list of default template parameters. After that, two other parameters are added. Now build this project and copy the output assembly to [<VS Install Path>\Common7\IDE] folder.   your designer is ready.     The template that you had created is now added to your VSIX project. In windows explorer open your template zip file (extract it somewhere). open the .vstemplate file. first of all remove <ProjectItem SubType="Code" TargetFileName="$fileinputname$.cs" ReplaceParameters="true">Messages.cs</ProjectItem> because the .cs file is not to be intended to be a part of template and it will be generated. change value of ReplaceParameters for your .tt file to true to enable parameter replacement in this file. now right after </TemplateContent> end element, write this: <WizardExtension>   <Assembly>Framework.Messages.Design</Assembly>   <FullClassName>Framework.Messages.Design.MessageDesigner</FullClassName> </WizardExtension>   one other thing that you should do is to edit your .tt file and remove your .cs file. Lines 8 and 9 of your .tt file should be:     var connectionString = "$connectionString$";     var systemName = "$systemName$"; this parameters will be replaced when the item is added to a project. Save the contents to a zip file with same file name and replace the original file.   now again build your VSIX project, uninstall your extension. close VS. now run .vsix file. open vs, add an item of type messages to your project, bingo, your wizard form will show up. fill the fields and click ok, values are replaced in .tt file added.     that’s it. tried so hard to make this post brief, hope it was not so long…   Cheers Maziar

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