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subql.js
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subql.js
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const graphql = require('graphql');
const { connected } = require('./socketdata.js');
const {JobQueue, Job} = require('./jobqueue.js');
const db = {};
const mroot = {};
const otypes = {};
const operations = {};
var storedSchema = '';
var jobQueue = new JobQueue();
jobQueue.addObservable("observable1", (job) => job.runTask(), (err) => console.log(err), () => console.log('complete'));
jobQueue.addObservable("observable2", (job) => job.runTask(), (err) => console.log(err), () => console.log('complete'));
jobQueue.addObservable("observable3", (job) => job.runTask(), (err) => console.log(err), () => console.log('complete'));
jobQueue.addObservable("observable4", (job) => job.runTask(), (err) => console.log(err), () => console.log('complete'));
function parseSchema(schema) {
if (!schema) {
throw new Error('parseSchema :: parseSchema must take in a schema string');
}
storedSchema = schema;
let schemaSource = new graphql.Source(schema);
let parsedSchema = graphql.parse(schema);
parsedSchema.definitions.forEach((ele) => {
if (ele.name.value === 'Query' || ele.name.value === 'Mutation') {
ele.fields.forEach((field) => {
operations[field.name.value] = {
name: field.name.value,
type: ele.name.value,
// for List Types, field.type.kind defines a list type and field.type.type.kind defines the named type
value: field.type.kind === "ListType" ? field.type.type.name.value : field.type.name.value,
kind: field.type.kind
}
});
}
});
}
function registerType(classFn, ...uniqKeys) {
if(typeof classFn !== 'function') {
throw new Error('registerType :: registerType must take in a constructor function as first argument');
}
if(!uniqKeys) {
throw new Error('registerType :: registerType did not recieve any keys as arguments');
}
otypes[classFn.name] = {
name: classFn.name,
classType: classFn,
keys: uniqKeys,
};
}
function registerResolver(...rootFn) {
if(!rootFn) {
throw new Error('registerResolver :: registerResolver must take at least one resolver function.');
}
rootFn.forEach((fn) => {
if(fn.name.length <= 0) {
throw new Error('registerResolver :: registerResolver can not take anonymous functions as arguments');
}
mroot[fn.name] = wrapResolver(fn);
});
}
/**
* wrapResolver will add the trigger functionality to notify clients
* for operations of type Mutation and not ListTypes
*/
function wrapResolver(fn) {
if(operations[fn.name].type === 'Mutation' && operations[fn.name].kind !== 'ListType') {
return function (...args) {
let ret = fn(...args);
triggerType(ret.constructor.name, ret);
return ret;
}
} else {
return fn;
}
}
function getSchema(){
return storedSchema;
}
function getRoot() {
return mroot;
}
/**
* handleSubscribe takes a query string and a socket it
* It will store the proper information necesary to allow mutations to
* use the socketid to notify clients about updates to data
*/
function handleSubscribe(query, socketid) {
const root = Object.assign({}, getRoot());
const parseQuery = graphql.parse(query.query);
let queryOperations = getOperationNames(parseQuery);
connected[socketid].query = query.query;
connected[socketid].operationFields = findFields(parseQuery, {});
queryOperations.forEach((resolverName) => {
if(operations[resolverName].kind === 'ListType') {
let queries = parseQuery.definitions.reduce((acc, curr) => {
return curr.operation === 'query' ? curr : acc;
}, { selectionSet: { selections: [] } });
let currentSelection = queries.selectionSet.selections.reduce((acc, curr) => {
return curr.name.value === resolverName ? curr : acc;
}, {});
let inputs = currentSelection.arguments.reduce((acc, curr) => {
acc[curr.name.value] = curr.value.value;
return acc;
}, {});
jobQueue.addJob(new Job(
resolverName + JSON.stringify(inputs),
() => root[resolverName](inputs),
(result) => {
let mutateddata = { data: {} };
mutateddata.data[resolverName] = result.map(val => queryFilter(val, connected[socketid]));
return connected[socketid] !== undefined
? connected[socketid].socket.emit(socketid, mutateddata)
: console.log(`[Job] :: client has disconnected`)},
socketid,
true
));
} else if(operations[resolverName].type === 'Query') {
let oldResolver = root[resolverName];
root[resolverName] = function (...args) {
let ret = oldResolver(...args);
let uniqIdentifier = generateUniqueIdentifier(operations[resolverName].value, ret);
db[uniqIdentifier] = !db[uniqIdentifier] ? [socketid] : [...db[uniqIdentifier], socketid];
return ret;
}
}
});
graphql.graphql(
graphql.buildSchema(storedSchema),
query.query,
root
).then((result) => {
if(connected[socketid]){
connected[socketid].socket.emit(socketid, result);
}else{
// client has disconnected.
// TODO add in logic for removing data about disconnected client
}
});
}
function getOperationNames(parsedQuery) {
let results = [];
parsedQuery.definitions.forEach( (definition) => {
if(definition.operation === 'query'){
definition.selectionSet.selections.forEach((curr) => {
results.push(curr.name.value);
});
}
});
return results;
}
/**
* Traverses through the parsed query and retrieves all the resolver names (fields)
*/
function findFields(parsedQuery, store) {
let collection = parsedQuery.definitions[0].selectionSet.selections;
function findFieldshelper(val, store) {
store[val.name.value] = [];
val.selectionSet.selections.forEach(field => {
if (field.selectionSet) {
store[val.name.value].push(findFieldshelper(field, {}));
} else {
store[val.name.value].push(field.name.value);
}
});
return store;
}
collection.forEach((val) => {
findFieldshelper(val, store);
});
return store;
}
function handleDisconnect(socketid) {
jobQueue.removeJob('identifier', socketid);
Object.keys(db).forEach((uniqIdentifier) => {
let socketIndex = db[uniqIdentifier].indexOf(socketid);
if(socketIndex >= 0) {
db[uniqIdentifier].splice(socketIndex, 1);
}
});
delete connected[socketid];
}
function triggerType(typename, resolverResult) {
if(otypes[typename] === undefined) {
throw new Error(`triggerType :: There exists no registered type named ${typename}`);
}
let uniqIdentifier = generateUniqueIdentifier(typename, resolverResult);
if(db[uniqIdentifier] !== undefined) {
db[uniqIdentifier].forEach((socket) => {
if (connected[socket] !== undefined) {
connected[socket].socket.emit(socket, queryFilter(resolverResult, connected[socket]));
}
});
}
};
function queryFilter(resolverResult, clientObj) {
let {list, matchedResolver} = determineList_Resolver(resolverResult, clientObj);
let retObjectTemplate;
let retObjFill;
if (list) {
retObjectTemplate = {};
retObjFill = retObjectTemplate;
} else {
retObjectTemplate = { data: {} };
retObjectTemplate.data[matchedResolver] = {};
retObjFill = retObjectTemplate.data[matchedResolver];
}
let fields = clientObj.operationFields[matchedResolver];
nestedQueryHelper(fields, resolverResult, retObjFill);
return retObjectTemplate;
}
// function name can be changed to be more relavent
function determineList_Resolver(resolverResult, clientObject) {
let typeOfObj = resolverResult.constructor.name;
let resolverNames = Object.keys(clientObject.operationFields);
let list = false;
let matchedResolver;
resolverNames.forEach((resolver) => {
if (operations[resolver].value === typeOfObj && operations[resolver].kind === "NamedType") {
matchedResolver = resolver;
} else if(operations[resolver].value === typeOfObj){
matchedResolver = resolver;
list = true;
}
});
return { list, matchedResolver };
}
// name may need to be changed since it works in general
// handles the entire query filtering process
function nestedQueryHelper(fieldArray, resolverObj, resultObj) { //TODO can we possibly refactor with similar code in query filter
fieldArray.forEach((key) => {
if(typeof key === 'object') {
let fieldKey = Object.keys(key)[0];
if (!Array.isArray(resolverObj[fieldKey])) {
resultObj[fieldKey] = nestedQueryHelper(key[fieldKey], resolverObj[fieldKey], {});
} else {
resultObj[fieldKey] = resolverObj[fieldKey].map(ele => nestedQueryHelper(key[fieldKey], ele, {}));
}
} else {
resultObj[key] = resolverObj[key];
}
});
return resultObj;
}
function generateUniqueIdentifier(typename, resolverResult) {
if(otypes[typename] === undefined) {
throw new Error(`generateUniqueIdentifier :: There exists no registered type named ${typename}`);
}
let uniqKeys = otypes[typename].keys;
return typename + uniqKeys.reduce((acc, curr) => {
return acc + curr + resolverResult[curr];
}, '');
}
module.exports = {
registerResolver,
getRoot,
getSchema,
registerType,
parseSchema,
handleSubscribe,
handleDisconnect,
triggerType
};