> If I visit /test_env/db_worker/call/json/work_service?a=1&b=2, I get the > right result. What I want is to be able to visit > /test_env/boss/order_service and get the exact same result. Right now, I > get "name 'service' is not defined" (because db.py is not run, and > "service" is defined there). >
Because work_service is defined as JSON-RPC service, the proper way to call it would be via an RPC call, as explained here: http://web2py.com/books/default/chapter/29/10/services#Accessing-JSONRPC-services-from-web2py. Otherwise, there is not much point in making it an RPC service. > Now, as near as I can tell, everything I've done above in db_worker.py is > straight out of the book as basic web2py stuff. But what you seem to be > saying is that, if I want to make "order" work, I have to significantly > change the way I've written db.py and worker.py. Namely, I have to abandon > the idea of the normal execution framework whereby model files are > automatically executed and dump their contents into the namespace of > controllers, and instead I have to factor out the db-creation code into a > separate module, and then, instead of having it automatically executed and > provided to the db_worker controller, I have to manually import and run > that db-creation code from within db_worker.py. Is that correct? > You make it sound more complicated than it is. If you need to share both a database and model definitions across applications, you can simply take the code you would otherwise have put in a model file and instead put it in a function in a module. Then in each app that needs it, import the function and run it. This involves maybe a couple extra lines of code in each app. Note, web2py already employs this approach to provide some of its functionality. Consider Auth and Scheduler -- both of those classes take a db object and define a number of models. Yet they are defined in modules and must be imported and instantiated in any given application that wants to use them. This is the standard mechanism for sharing code in Python. > If so, I understand what you're saying, but I guess it seems a bit > perverse. Web2py has all this nice magic for automatically deciding which > model files to run, running them, and automatically providing the names > they define to the controller files. It's great and makes things very > convenient and reduces boilerplate. But that all has to go out the window > for one controller to access another (even within the same app)? > The workflow of an HTTP request involves things like setting up the session, and some of the code (particularly controller code) may depend on attributes of the request object. If you want to make what amounts to an internal HTTP request to another app or controller, it will not be clear what elements of the current request to retain (e.g., should the current session, request headers, query string, etc. be replicated in the second call?). Note, you can achieve this to some extent by calling gluon.shell.env and passing in some or all of the current request attributes via the extra_request parameter, but things can get messy very quickly. Should everything happen in the same database transaction? What if there is a redirect or HTTP exception in the second app? You will generally be better off isolating full HTTP requests to a single app. > Is there no way to say "do everything just as you would if a request came > in for it -- that is, run the model files and the controller file -- but > just don't actually create a request or call any of the controller > functions yet, just return me an object representing the controller file"? > I wonder how often you really need to do something like this. If there is some common set of functionality that needs to be shared across apps, it probably does not have to be in the form of a controller function, but could instead be a more general function that can be used as part of a controller. Again, consider how the Auth functionality works -- it does not provide a set of ready-made controller functions but instead provides a mechanism to (a) define a common set of database tables and (b) expose methods that can be called from within controllers where needed. Do you have a use case that cannot easily be accommodated by that pattern? If so, what do you imagine would be the API for doing what you want to do, and would it look much different from simply making an HTTP call (or possibly an RPC call) to the other app (which you can already do)? Anthony -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
