|
| 1 | +from graphql.type import ( |
| 2 | + GraphQLField, |
| 3 | + GraphQLObjectType, |
| 4 | + GraphQLSchema, |
| 5 | + GraphQLString, |
| 6 | +) |
| 7 | + |
| 8 | +from graphql import graphql |
| 9 | +import threading |
| 10 | +from promise import dataloader, promise |
| 11 | + |
| 12 | + |
| 13 | +REQUEST_GLOBALS = threading.local() |
| 14 | + |
| 15 | + |
| 16 | +def viewer_id_resolver(root, info, **args): |
| 17 | + return REQUEST_GLOBALS.current_user_id |
| 18 | + |
| 19 | + |
| 20 | +def promise_viewer_id_resolver(root, info, **args): |
| 21 | + return promise.Promise.resolve(None).then(lambda x: REQUEST_GLOBALS.current_user_id) |
| 22 | + |
| 23 | + |
| 24 | +class UserIdLoader(dataloader.DataLoader): |
| 25 | + def batch_load_fn(self, user_ids): |
| 26 | + return promise.Promise.resolve(user_ids) |
| 27 | + |
| 28 | + |
| 29 | +user_id_loader = UserIdLoader() |
| 30 | + |
| 31 | + |
| 32 | +def dataloader_viewer_id_resolver(root, info, **args): |
| 33 | + return user_id_loader.load(REQUEST_GLOBALS.current_user_id) |
| 34 | + |
| 35 | + |
| 36 | +queryType = GraphQLObjectType( |
| 37 | + "Query", |
| 38 | + fields=lambda: { |
| 39 | + "viewerId": GraphQLField( |
| 40 | + GraphQLString, |
| 41 | + resolver=viewer_id_resolver, |
| 42 | + ), |
| 43 | + "promiseViewerUserId": GraphQLField( |
| 44 | + GraphQLString, |
| 45 | + resolver=promise_viewer_id_resolver, |
| 46 | + ), |
| 47 | + "dataloaderViewerUserId": GraphQLField( |
| 48 | + GraphQLString, |
| 49 | + resolver=dataloader_viewer_id_resolver, |
| 50 | + ), |
| 51 | + |
| 52 | + }, |
| 53 | +) |
| 54 | + |
| 55 | +Schema = GraphQLSchema(query=queryType) |
| 56 | + |
| 57 | + |
| 58 | +def handle_request(session, query, variables={}): |
| 59 | + # Authenticate requests and set global user id |
| 60 | + # https://django-globals.readthedocs.io/en/latest/#usage |
| 61 | + # https://flask.palletsprojects.com/en/1.1.x/appcontext/ |
| 62 | + REQUEST_GLOBALS.current_user_id = session.get('userId') |
| 63 | + |
| 64 | + return graphql(Schema, query, variables) |
| 65 | + |
| 66 | + |
| 67 | +def send_request(user_id, query): |
| 68 | + session = {"userId": user_id} |
| 69 | + i = 0 |
| 70 | + while i < 1000: |
| 71 | + i += 1 |
| 72 | + |
| 73 | + result = handle_request(session, query) |
| 74 | + if result.errors: |
| 75 | + raise Exception('Execution error', result.errors) |
| 76 | + if 'viewerId' not in result.data: |
| 77 | + raise Exception('Missing data', result.data) |
| 78 | + assert result.data['viewerId'] == user_id, \ |
| 79 | + "request #{}: logged in user {} - actual user {}".format(str(i), user_id, result.data['viewerId']) |
| 80 | + |
| 81 | + |
| 82 | +def simulate_concurrent_requests(query): |
| 83 | + threads = [threading.Thread(target=send_request, args=(user_id, query)) for user_id in ['1', '2']] |
| 84 | + |
| 85 | + for thread in threads: |
| 86 | + thread.start() |
| 87 | + |
| 88 | + for thread in threads: |
| 89 | + thread.join() |
| 90 | + |
| 91 | + |
| 92 | +def test_regular_field(): |
| 93 | + simulate_concurrent_requests(""" |
| 94 | + query { |
| 95 | + viewerId |
| 96 | + } |
| 97 | + """) |
| 98 | + |
| 99 | + |
| 100 | +def test_promised_field(): |
| 101 | + simulate_concurrent_requests(""" |
| 102 | + query { |
| 103 | + viewerId: promiseViewerUserId |
| 104 | + } |
| 105 | + """) |
| 106 | + |
| 107 | + |
| 108 | +def test_dataloader_field(): |
| 109 | + simulate_concurrent_requests(""" |
| 110 | + query { |
| 111 | + viewerId: dataloaderViewerUserId |
| 112 | + } |
| 113 | + """) |
| 114 | + |
| 115 | + |
| 116 | +# Run this directly |
| 117 | +# PyTest does not report exceptions happening in threads |
| 118 | +if __name__ == '__main__': |
| 119 | + test_regular_field() |
| 120 | + test_promised_field() |
| 121 | + test_dataloader_field() |
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