What is GraphQL?
GraphQL is a query language for APIs
from: https://graphql.org/
We got a result by throwing POST request to one endpoint.
The curl command below is an example to get messages.
$ curl -H "Content-Type: application/json" -X POST -d ' { "query": "{ messages { name body } }" } ' http://xxxxxxxxxxxxxxxxxx-cn-shanghai.alicloudapi.com/
{"data":{"messages":[{"body":"Hello","name":"asmsuechan"},{"body":"World","name":"suechan"}]}} For more information, please google graphql. I don't go detailed explanations about it in this article.
Minimum Code
First, I wrote the minimum GraphQL code and made it work on Function Compute.
I expected the combination of query and return value below:
Query: "{ hello }" Return Value: { data: { hello: "world" } } This sample below came from Official GitHub.
// index.js const { hook } = require('fc-helper'); const { graphql, GraphQLSchema, GraphQLObjectType, GraphQLString } = require('graphql'); const schema = new GraphQLSchema({ query: new GraphQLObjectType({ name: 'RootQueryType', fields: { hello: { type: GraphQLString, resolve() { return 'world'; } } } }) }); const query = '{ hello }'; module.exports.handler = (event, context, callback) => { graphql(schema, query).then((result) => { callback(null, { statusCode: 200, body: result }); }); }); It's easy. Just exec graphql() in the handler function.
More detailed API
Next, I made the API better. I expected the combination of query and return values below"
Query: "{ messages { name body } }" Return value: {"data":{"messages":[{"body":"Hello","name":"asmsuechan"},{"body":"World","name":"suechan"}]}} I defined a type named message to get plural message.
// index.js const { hook } = require('fc-helper'); const { graphql, GraphQLSchema, GraphQLObjectType, GraphQLList, GraphQLString } = require('graphql'); const atob = require('atob'); const messages = [ { name: 'asmsuechan', body: 'Hello' }, { name: 'suechan', body: 'World' } ]; const schema = new GraphQLSchema({ query: new GraphQLObjectType({ name: 'RootQueryType', fields: { messages: { type: GraphQLList( new GraphQLObjectType({ name: 'message', fields: { name: { type: GraphQLString }, body: { type: GraphQLString }, }, }), ), resolve() { return messages; } } } }) }); module.exports.handler = (event, context, callback) => { const request = JSON.parse(event.toString('utf8')) const query = JSON.parse(atob(request["body"]))["query"] graphql(schema, query).then((result) => { callback(null, { statusCode: 200, body: result }); }); }; I saw it works fine by executing curl.
$ curl -H "Content-Type: application/json" -X POST -d ' { "query": "{ messages { name body } }"} 'http://xxxxxxxxxxxxxxxxxx-cn-shanghai.alicloudapi.com/ {"data":{"messages":[{"body":"Hello","name":"asmsuechan"},{"body":"World","name":"suechan"}]}} Conclution
It's very happy to use GraphQL instead of REST API on Function Compute + API Gateway because we can create complex APIs without many API Gateways.
However, it's too fast to run as production environment.
Here's my repository of this article:
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