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Merged
enisdenjo merged 6 commits into from
Oct 19, 2020
Merged

feat(server): Support returning multiple results from execute #28

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688f350
feat(execution): support returning AsyncIterableIterator from execute
n1ru4l Oct 17, 2020
1551ed2
docs: adjust protocol
enisdenjo Oct 19, 2020
b1f8781
style: shorter wording
enisdenjo Oct 19, 2020
a6e5998
refactor: clearer distinction
enisdenjo Oct 19, 2020
b7d42b9
refactor: execute can promise an iterator
enisdenjo Oct 19, 2020
99c9afa
docs: differentiate `execute` and `subscribe`
enisdenjo Oct 19, 2020
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154 changes: 85 additions & 69 deletions src/server.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,12 @@ export interface ServerOptions {
* execute the subscription operation
* upon.
*/
execute: (args: ExecutionArgs) => Promise<ExecutionResult> | ExecutionResult;
execute: (
args: ExecutionArgs,
) =>
| Promise<ExecutionResult>
| ExecutionResult
| AsyncIterableIterator<ExecutionResult>;
/**
* Is the `subscribe` function
* from GraphQL which is used to
Expand Down Expand Up @@ -457,59 +462,65 @@ export function createServer(
});
}

// perform
if (operationAST.operation === 'subscription') {
const subscriptionOrResult = await subscribe(execArgs);
if (isAsyncIterable(subscriptionOrResult)) {
// iterable subscriptions are distinct on ID
if (ctx.subscriptions[message.id]) {
return ctx.socket.close(
4409,
`Subscriber for ${message.id} already exists`,
);
}
ctx.subscriptions[message.id] = subscriptionOrResult;

try {
for await (let result of subscriptionOrResult) {
// use the root formater first
if (formatExecutionResult) {
result = await formatExecutionResult(ctx, result);
}
// then use the subscription specific formatter
if (onSubscribeFormatter) {
result = await onSubscribeFormatter(ctx, result);
}
await sendMessage<MessageType.Next>(ctx, {
id: message.id,
type: MessageType.Next,
payload: result,
});
}
const asyncIterableHandler = async (
asyncIterable: AsyncIterableIterator<ExecutionResult>,
) => {
// iterable subscriptions are distinct on ID
if (ctx.subscriptions[message.id]) {
return ctx.socket.close(
4409,
`Subscriber for ${message.id} already exists`,
);
}
ctx.subscriptions[message.id] = asyncIterable;

const completeMessage: CompleteMessage = {
id: message.id,
type: MessageType.Complete,
};
await sendMessage<MessageType.Complete>(ctx, completeMessage);
if (onComplete) {
onComplete(ctx, completeMessage);
try {
for await (let result of asyncIterable) {
// use the root formater first
if (formatExecutionResult) {
result = await formatExecutionResult(ctx, result);
}
} catch (err) {
await sendMessage<MessageType.Error>(ctx, {
// then use the subscription specific formatter
if (onSubscribeFormatter) {
result = await onSubscribeFormatter(ctx, result);
}
await sendMessage<MessageType.Next>(ctx, {
id: message.id,
type: MessageType.Error,
payload: [
new GraphQLError(
err instanceof Error
? err.message
: new Error(err).message,
),
],
type: MessageType.Next,
payload: result,
});
} finally {
delete ctx.subscriptions[message.id];
}

const completeMessage: CompleteMessage = {
id: message.id,
type: MessageType.Complete,
};
await sendMessage<MessageType.Complete>(ctx, completeMessage);
if (onComplete) {
onComplete(ctx, completeMessage);
}
} catch (err) {
await sendMessage<MessageType.Error>(ctx, {
id: message.id,
type: MessageType.Error,
payload: [
new GraphQLError(
err instanceof Error
? err.message
: new Error(err).message,
),
],
});
} finally {
delete ctx.subscriptions[message.id];
}
};

// perform
if (operationAST.operation === 'subscription') {
const subscriptionOrResult = await subscribe(execArgs);
if (isAsyncIterable(subscriptionOrResult)) {
await asyncIterableHandler(subscriptionOrResult);
} else {
let result = subscriptionOrResult;
// use the root formater first
Expand Down Expand Up @@ -539,27 +550,32 @@ export function createServer(
// operationAST.operation === 'query' || 'mutation'

let result = await execute(execArgs);
// use the root formater first
if (formatExecutionResult) {
result = await formatExecutionResult(ctx, result);
}
// then use the subscription specific formatter
if (onSubscribeFormatter) {
result = await onSubscribeFormatter(ctx, result);
}
await sendMessage<MessageType.Next>(ctx, {
id: message.id,
type: MessageType.Next,
payload: result,
});

const completeMessage: CompleteMessage = {
id: message.id,
type: MessageType.Complete,
};
await sendMessage<MessageType.Complete>(ctx, completeMessage);
if (onComplete) {
onComplete(ctx, completeMessage);
if (isAsyncIterable(result)) {
await asyncIterableHandler(result);
} else {
// use the root formater first
if (formatExecutionResult) {
result = await formatExecutionResult(ctx, result);
}
// then use the subscription specific formatter
if (onSubscribeFormatter) {
result = await onSubscribeFormatter(ctx, result);
}
await sendMessage<MessageType.Next>(ctx, {
id: message.id,
type: MessageType.Next,
payload: result,
});

const completeMessage: CompleteMessage = {
id: message.id,
type: MessageType.Complete,
};
await sendMessage<MessageType.Complete>(ctx, completeMessage);
if (onComplete) {
onComplete(ctx, completeMessage);
}
}
}
break;
Expand Down
81 changes: 81 additions & 0 deletions src/tests/server.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -559,6 +559,87 @@ describe('Subscribe', () => {
await wait(20);
});

it('should execute a query operation with custom execute that returns a AsyncIterableIterator, "next" the results and then "complete"', async () => {
expect.assertions(5);

await makeServer({
schema,
execute: async function* () {
for (const value of ['Hi', 'Hello', 'Sup']) {
yield {
data: {
getValue: value,
},
};
}
},
});

const client = new WebSocket(url, GRAPHQL_TRANSPORT_WS_PROTOCOL);
client.onopen = () => {
client.send(
stringifyMessage<MessageType.ConnectionInit>({
type: MessageType.ConnectionInit,
}),
);
};

let receivedNextCount = 0;
client.onmessage = ({ data }) => {
const message = parseMessage(data);
switch (message.type) {
case MessageType.ConnectionAck:
client.send(
stringifyMessage<MessageType.Subscribe>({
id: '1',
type: MessageType.Subscribe,
payload: {
operationName: 'TestString',
query: `query TestString {
getValue
}`,
variables: {},
},
}),
);
break;
case MessageType.Next:
receivedNextCount++;
if (receivedNextCount === 1) {
expect(message).toEqual({
id: '1',
type: MessageType.Next,
payload: { data: { getValue: 'Hi' } },
});
} else if (receivedNextCount === 2) {
expect(message).toEqual({
id: '1',
type: MessageType.Next,
payload: { data: { getValue: 'Hello' } },
});
} else if (receivedNextCount === 3) {
expect(message).toEqual({
id: '1',
type: MessageType.Next,
payload: { data: { getValue: 'Sup' } },
});
}
break;
case MessageType.Complete:
expect(receivedNextCount).toEqual(3);
expect(message).toEqual({
id: '1',
type: MessageType.Complete,
});
break;
default:
fail(`Not supposed to receive a message of type ${message.type}`);
}
};

await wait(20);
});

it('should execute the query of `DocumentNode` type, "next" the result and then "complete"', async () => {
expect.assertions(3);

Expand Down