Interpreted languages such as PHP allow a separate file, often called config.php, to contain string constants such as server names. This facilitates deployment, as the config file is simply not uploaded when the code is updated - the server names, e.g. for REST transactions, are typically different in the deployment environment.
In Dart, since it is compiled, this approach does not work. If there are server name constants which are referred to in the HTML via {{ }}, it seems the code must be recompiled before deployment.
Is there a way to specify string constants in such a way to avoid this recompilation requirement?
There are a couple of options I can think of:
One trick is to put configuration in a map keyed by hostname. At runtime, look up the configuration from the map, using window.location as a key. This will allow configuration to be baked into the Dart source, yet still allow different values to be specified for different environments.
If you want to be able to change your configuration after compilation, you can embed it as JSON within the HTML source, or load it via an HTTP request. (This isn't using a constant as asked, however, by definition it's not possible to change a constant after compile time)
Ok, so short answer is "You can't" - at the moment. But the Dart team are aware of this limitation, and are discussing it in dartlang as per the comment above.
Related
change a config.properties file in a jar / war file in runtime and hotdeploy the changes ?
my requirement is something as follows, we have a "config.properties" in a jar/war file , i have to open the file through a webpage and after the user has made necessary changes to it, i have to update the "config.properties" in jar/war file and hot deploy it. can we achieve this feat ? if so can you please point me to relevant sites/documents so that i can jumpstart on this.
I will strongly recommend your architecht rethink this solution. What you describe should be done through JNDI or a similar technique, not through reloading properties.
Deployments should be considered static - that any given web container allows for magic trickery should not be depended on, and WILL break some day (most likely at the most inconvenient time).
You've got a couple of problems off the top of my head:
ensuring that nothing is holding static references to a java.util.Properties that has previously loaded your config.properties file.
most servlet engines will unpack your war to a working directory so the properties file you load won't be the one in the war, it will be the unpacked one. This means your changes
will be overwritten when you restart the servlet engine because this is typically one of the points the war is unpacked.
While these problems aren't insurmountable I've always found it much easier to implement this sort of behavior by storing the properties in JNDI (as Thorbjørn suggests) or a database (while being careful about the static references I mentioned in point 1).
The JNDI/database solution has the nice side effect of easing deployment into multiple environments because each typically has it's own registry/database.
Even that I agree with the comments explained before, I could suggest one solution:
Apache Commons Configuration extension gives you the posibility to do something like:
config.setReloadingStrategy(new FileChangedReloadingStrategy());
That could make the trick to change the configuration file on a runtime basis with no code at all.
However, like JNDI and other methods of web application configuration, the security is a concern. Be careful on which parameters you can/must be able to configure.
This is a (actually it is several) follow-up question to my previous question on F# Type Providers and Continuous Integration.
It seems to me that it would be a good idea to use the SqlDataConnection type provider as a compile-time check that the code/database integrity remains intact in feature-branch driven development; you would know at every commit/build that no changes have been made to the code that has not also been applied to the database, assuming that building the database is also a part of your CI process.
However, a couple of questions arise:
The name (as well as the location) of the config file is not the same at compile time as at runtime, e.g. app.config -> MyApp.exe.config, which will result in a runtime error if you try to use
SqlDataConnection<ConnectionStringName="DbConnection", ConfigFile="app.config">
(Actually, specifying ConfigFile="app.config" is not necessary, since it is the default value.)
The runtime error can be avoided by copying the app.config file to the output directory (there’s a setting for that), but that would result in having both an app.config and a MyApp.exe.config file in the output directory. Not very pretty. Adding a separate configuration file for type providers would be another solution, but imho that’s not very pretty either.
Question: Has anyone come up with a more elegant solution to this problem?
The next problem arises when you come to the build server. It is most likely that you don’t want to compile against the same database as you did while developing, thus requiring a different connection string. And yes, in production you’d need yet another one.
Question: How do you go about solving this in the most convenient way? Remember, the solution has to be a working part of a CI process!
This strategy would require generating the database on each build at the build server, probably from a baseline script with some feature/sprint update scripts.
Question: Has anyone tried this and how did it affect build times? If yes, how did you create this step?
At runtime you can use the GetDataContext overload that accepts a connection string. See here: Providing connection string to Linq-To-Sql data provider
I am familiar with the solution that #Gustavo proposes, but I’ve always felt that there is something fishy about it. Something about having to specify the connection string twice… However, when I once again got the same reply, I slowly started to realize that the answer must be correct, and that it’s me who’s thinking wrong. These are my conclusions:
The reply states that you can use the GetDataContext overload that accepts a connection string. If you change this to should, things become clearer, at least to me.
The thing is that I’ve been thinking of the class definition as both a compile-time directive and as a run-time variable, but even though this is possible, it is hardly a good idea. The default value of the ConfigFile argument is as we’ve already seen “app.config”, but that file doesn’t exist (with that name) at run-time, so it doesn’t make sense to try to use it, thus leaving GetDataContext as the only reasonable option. I suggest that you do this:
Keep your compile-time settings in a file called compilation.config (or whatever you prefer) and specify this file for usage in the class definition.
Use the GetDataContext overload that accepts a connection string for run-time resolution and specify this connection string in the app.config file.
You will end up with something looking like this:
type private dbSchema = SqlEntityConnection<ConnectionStringName="DbConnection", ConfigFile="compilation.config">
let private db = dbSchema.GetDataContext(ConfigurationManager.ConnectionStrings.["DbConnection"].ConnectionString)
Heck, this even supports the SRP; compile-time settings in one file and run-time settings in another!
Regarding the rest of my questions, I assume that the answer lies in some scripting in the Continuous Deployment pipeline. Still interested in other solutions though.
We have to maintain a lot of classic ASP and VB/ASP.Net applications that link to many different parts of a static website.
The master pages are littered with various
<!-- #include virtual="/site/footer.something" -->
and similar, where there are many many combinations of what /site/ can be.
The problem is, when you're debugging etc. when you try to run one of these sites locally, you're almost guaranteed to get a parser error.
What I want to do is come up with a generic handler so that I can just insert a blank file for any #include file that doesn't exist.
I tried to setup a URL Rewrite rule, which works in the browser (just redirects to an empty html file) but I'm guessing the ASP parser doesn't include as a webrequest as it still generates a parser error.
I don't want to have to copy the static content to my workstation everytime I open a new app and I don't want to edit the master pages to exclude the links as one day I'm just going to forget and deploy something broken.
So the question is, is there a way to serve a default file for these declarations, or some other method ?
Edit: To consider a different fix to this problem; is there some way to insert some kind of file-system handler that can pick up requests for missing files in specific locations and return predefined content ?
Yeah, I know that's a really offbeat direction and probably a very bad idea in practise, but this is quite a frustrating problem in the office now.
What's irritating is that even though IIS has SSI disabled, the ASP processer still honours #include directives. Is there a way to either disable that, or perhaps some way to override the behaviour in some kind of generated class ?
The problem you will encounter is that includes are processed before any of your code runs. The server gathers all of the resources referenced in the scripts then compiles and runs your code. By the time your code is running, the missing include has already thrown a compiler error.
Further, what you're asking could potentially run into other problems. Often times includes contain code (procedures, constants, variable declarations, etc.) that other scripts rely on. So, even if you were to replace the missing include with an empty file, you still may encounter other parser errors if the including script expects that include to contain specific code.
Probably your best bet is to make a console app or something similar that parses your files looking for the include statements, resolves the relative path based on your directory structure and does what you want - write an empty file if it doesn't exist. You could then run your projects through this parser and at least eliminate that issue.
Additionally, you mention the possibility of accidentally deploying something that you've edited to circumvent this problem. I would assume then, that if you were to write out these "dummy" includes, there is no possibility of you accidentally deploying them and overwriting good files?
I'm having some trouble merging the localization satellite assemblies into the plugin DLL for CRM2011.
Either that, or I don't know how to use the merged resources afterwards.
I create a few plugins and create a basic resource file (default - English) and one for a specific culture (at the time of writing it's for Polish localizations, but later I'll need to add French as well).
I make sure not to sign the assembly itself, as ILMerge will sign the finished assembly itself.
This is the command I use to merge the extra satellite assembly:
ilmerge /targetplatform:v4,C:\Windows\Microsoft.NET\Framework\v4.0.30319 /log:log.txt /keyfile:KeyFile.snk /out:Plugins.dll DynamicsCRM2011.Plugins.dll pl-PL\DynamicsCRM2011.Plugins.resources.dll
As you can see, the plugins are in .NET 4.0 and I've got the required .config file for ILMerge to use the required assemblies for merging.
The generated file appears fine, I can register it with CRM plugin-registrator, add new steps and so forth.
However, it will always use the default language. I've tried changing the System.Threading.Thread.CurrentThread.UICulture, but this didn't help. When I created a ResourceManager class and used GetString("ErrorMessage", new System.Globalization.CultureInfo("pl-PL")), I got an Exception that the specified ResourceManager doesn't know what to do with the specified culture.
I know of this question here. However, the posted solution seems to be an old one. The generated resource .cs files do not use a ComponentResourceManager. Also, parts of the code posted there have been marked as deprecated.
I'm not really sure what I'm am to do now, or how to further debug this, as I have very little experience when it comes to working with assemblies themselves. Please, help me get those satellite assemblies under control.
Update:
I've been working with sandbox plugins for a while now, and thus I no longer have access to things such as CurrentCulture (or at least I cannot change such things). I've tried tackling this problem once more: I've created a simple plugin which is fired when a new Account is saved. Nothing fancy. Here's the actual plugin code:
ResourceManager rm = new ResourceManager(typeof(Properties.Resources));
var s = rm.GetString("ErrorAlreadyPosted", new System.Globalization.CultureInfo("pl-PL"));
throw new InvalidPluginExecutionException(s);
The code no longer throws an exception about not being able to find the specified culture... also the code obviously throws an exception at the end, but the important thing is WHAT the exception message is. I'd expect it to be in Polish.
Alas, it is not. The string returned by GetString is still in English.
The command I used for ILmerge is the same as before, but with the /lib parameter specified so that I don't have to copy all the CRM SDK dlls...
Apparently it is not possible to read resources from with the context of a Plugin.
Read up on MSDN: http://msdn.microsoft.com/en-us/library/hh670609.aspx#BKMK_UseXMLWebResourcesAsLanguageResources
Quote: When a plug-in requires localized text, you can use an XML web resource to store the localized strings so the plug-in can access them when needed. The structure of the XML is your option, but you may want to follow the structure used by ASP.NET Resource (.resx) files to create separate XML web resources for each language. For example, the following is an XML web resource named localizedString.en_US that follows the pattern used by .resx files.
This is all I know so far - have yet to build my own solution for localization of a crm plugin.
If you use a reflector tool to look at the generated assembly, do you see your resource(s) embedded correctly? You may be experiencing the bug as outlined in the link you posted.
Try setting Thread.CurrentThread.CurrentUICulture and\or Thread.CurrentThread.CurrentCulture.
Also try hooking into the AppDomain.CurrentDomain.AssemblyLoad and\or AppDomain.CurrentDomain.AssemblyResolve to debug which assemblies are being attempted to load and from where. You might need to customize their behavior so that instead of loading an external assembly to load an internal resource instead.
You can try embedding project references as resources instead of using ilmerge as well.
See this: http://bartlomiej.net/dotnet/embeded-assembies-into-an-executable/
The way we eventually handled this is by adding the localization XML files (generated by Visual Studio) as CRM resources, and created a bit of custom code which seeks the appropriate resource and then seeks the localization text inside.
It's, obviously, not as simple as just using the generated C# localization class, and requires some prep work. However, with that prep-work in place and with using nameof it's now almost as simple as the aforementioned resource classes.
I am using someone else's library that provides its own scripting host instance, it appears.
This lib provides me with functions to define the type of scripting language such as "jscript" and "vbscript", and I can supply it with script code and have that executed, with passing arguments in and back. So, basically, it works.
However, when I try to access the "WScript" object, I get an exception saying that this keyword is undefined.
The developer, not knowing much about this either (he only made this lib for me because I do not want to deal with Windows SDKs right now), told me that he is using "IScriptControl" for this.
Oh, and the lib also provides flags to allow "only safe subset" and "allow UI", which I set to false and true, respectively.
Does that ring a bell with anyone? Do a user of IScriptControl have to take extra steps in order to make a WScript object available? Or, can he use IScriptControl in a way that this is supplied automatically, just as when running the same script from wscript.exe?
Basically, all I need is the WScript.CreateObject function in order to access another app's API via COM.
I don't know why WScript is not known, but I suspect it is because the script host doesn't provide it. Maybe only wscript.exe does this.
If you are using Javascript, to create an object you can use new ActiveXObject(). If you are using VBScript, you can just use CreateObject.
See this article for some background.