Oneshot middleware

[Speedy1991]

Hi!
Currently I'm trying to add some one-shot-middlewares to the graphene schema (e.g. version check, policy check). The problem is, that the middleware get's fired for each field instead for a single request.
I can't use the DjangoMiddlewares because the error doesn't get wrapped into the graphql response error field

I found 2 solutions for this problem:

1. I set a variable _skip=False in the middleware which is toggled to True before the first next(...) call, e.g.:

lass LatestPolicyAcceptedMiddleware:

    def __init__(self, *args, **kwargs):
        super(LatestPolicyAcceptedMiddleware, self).__init__(*args, **kwargs)
        self._skip = False

    def resolve(self, next, root, info, **kwargs):
        if self._skip:
            return next(root, info, **kwargs)
        ...
        self._skip = True
        return next(root, info, **kwargs)

Well - that works but feels really odd.

2. Patching the GraphQLView.get_response method like this:

    def get_response(self, request, data, show_graphiql=False):
        try:
            check_min_native_version(request)
            latest_policy_check(request)
            return super(PatchedGraphQLView, self).get_response(request, data, show_graphiql)
        except (PolicyRequiredException, UpgradeNeededException) as e:
            result = self.json_encode(request, {"errors": [self.format_error(e)], "data": None}, pretty=show_graphiql)
            status_code = e.code
            return result, status_code

This feels also odd, but a way cleaner.

So - what's the best way to integrate a one-time middleware? It feels like the framework is missing this essential feature.

[melvinkcx]

I'm running into this issue as well, I have a middleware that checks the auth of the user and it is being consistently called for each field.

[melvinkcx]

Graphene middleware is called at a field-level, each field resolution would trigger calls to all middleware. I'm not sure if graphene will support request-level middleware, I just created an issue: graphql-python/graphene#1117

For now, what I do is add an attribute into info.context object and toggle that to indicate should the middleware logic be executed.

class AuthMiddleware:
    def resolve(self, next, root, info, **kwargs):
        if not hasattr(info.context, "auth_checked") and info.context.auth_checked:
            # Check user auth
            info.context.auth_checked = True
            
        return next(root, info, **kwargs)

[mrfoxes]

Graphene middleware is called at a field-level, each field resolution would trigger calls to all middleware. I'm not sure if graphene will support request-level middleware, I just created an issue: graphql-python/graphene#1117

For now, what I do is add an attribute into info.context object and toggle that to indicate should the middleware logic be executed.

class AuthMiddleware:
    def resolve(self, next, root, info, **kwargs):
        if not hasattr(info.context, "auth_checked") and info.context.auth_checked:
            # Check user auth
            info.context.auth_checked = True
            
        return next(root, info, **kwargs)

It's the same problem i'm noticing in my case but as you can see the middleware, despite not executing the logic runs anyway without executing nothing and so we're wasting execution time.
Assuming that you're requesting just one field it'll be fine but when you request a lot of fields can became a real bottleneck

Any idea so that we just run the middleware once for a specific context of execution?

[melvinkcx]

I just released graphql-utilities including utilities to support operation-level only middleware. It targets graphql-core>=3.0 (or graphql-core-next), feel free to check it out.

[Speedy1991]

@melvinkcx Thank you for this package

Just copied the run_only_once decorator into my own code because I don't want to have another dependency for 10 lines of code :)

it would be awesome if the run_only_once decorator can be picked into graphene_django
Whats your opinion @zbyte64 ?

[mrfoxes]

@melvinkcx Thank you for this package

Just copied the run_only_once decorator into my own code because I don't want to have another dependency for 10 lines of code :)

it would be awesome if the run_only_once decorator can be picked into graphene_django
Whats your opinion @zbyte64 ?

I've tried also the decorator but turn out for me that the middleware run just once and at the first request only, then for the others isn't just executed

@melvinkcx Can you confirm the behaviour?

[melvinkcx]

Only the decorated middleware would run once. Any other undecorated middlewares should execute at field-level as usual.

…

On Wed, Feb 5, 2020 at 7:57 AM MrFoxes ***@***.***> wrote: @melvinkcx <https://github.com/melvinkcx> Thank you for this package Just copied the run_only_once decorator into my own code because I don't want to have another dependency for 10 lines of code :) it would be awesome if the run_only_once decorator can be picked into graphene_django Whats your opinion @zbyte64 <https://github.com/zbyte64> ? I've tried also the decorator but turn out for me that the middleware run just once and at the first request only, then for the others isn't just executed @melvinkcx <https://github.com/melvinkcx> Can you confirm the behaviour? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#810?email_source=notifications&email_token=AEBBQ4INUPTI4P4N2HSFJ73RBHXGBA5CNFSM4JNJN722YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEKZQDUQ#issuecomment-582156754>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEBBQ4OW46IKCRYPZHRFPKLRBHXGBANCNFSM4JNJN72Q> .

[richin13]

I've tried also the decorator but turn out for me that the middleware run just once and at the first request only, then for the others isn't just executed

I confirm this behaviour is also happening to me. I need my middleware to execute at request level but with run_only_once it executes only on the first request

[melvinkcx]

@richin13 @mrfoxes This issue is fixed and is now available in graphql-utilities>=0.2.0.

[divyanshusoni21]

@melvinkcx if you could just tell how to use run_only_once decorator in my django-graphql project . it would be a great help.
PS. : i have gone thorugh the documentation of graphql-utilities project.