Got it working!

This commit is contained in:
2020-03-16 06:31:29 +11:00
parent a985e496a8
commit e9655f1055
3 changed files with 95 additions and 11 deletions

View File

@@ -5,7 +5,7 @@ const main = (schema, handler) => {
console.log(typeGraph);
//the receiving function - this will be called multiple times
return reqBody => {
return async reqBody => {
//parse the query
const tokens = reqBody.split(/(\s+)/).filter(s => s.trim().length > 0);
let pos = 0;
@@ -22,11 +22,10 @@ const main = (schema, handler) => {
//no leading keyword - regular query
default:
parseQuery(handler, tokens, pos, typeGraph);
const result = await parseQuery(handler, tokens, pos, typeGraph[tokens[pos]], typeGraph);
return [200, ''];
return [200, result];
//TODO
break;
}
}
@@ -135,8 +134,73 @@ const parseCompoundType = (tokens, pos) => {
return compound;
};
const parseQuery = (handler, tokens, pos, typeGraph) => {
//TODO
const parseQuery = async (handler, tokens, pos, typeGraph, superTypeGraph, parent = null) => {
//returns an object result from handler
//get the "parent object" contents for sub-objects
const queryName = superTypeGraph[tokens[pos]] ? null : tokens[pos]; //if you're a type, name = null
const queryType = superTypeGraph[tokens[pos]] ? tokens[pos] : superTypeGraph[parent.typeName][tokens[pos]].typeName; //use this type or derive the type from the parent
//move on
pos++;
//the opening brace
if (tokens[pos++] != '{') {
throw 'Expected \'{\' in query, found ' + tokens[pos - 1];
}
//the scalars to pass to the handler
const scalarFields = [];
const deferredCalls = []; //functions (promises) that will be called at the end of this function
while(tokens[pos] != '}') { //while not at the end of this block
//not the end of the query
if (!tokens[pos]) {
throw 'Expected field in query, got end';
}
//prevent using keywords
if (['create', 'update', 'delete', 'set', 'match'].includes(tokens[pos])) {
throw 'Unexpected keyword ' + tokens[pos];
}
//type is a scalar, and can be queried
if (superTypeGraph[typeGraph[tokens[pos]].typeName].scalar) {
//push the scalar object to the queryFields
scalarFields.push({ typeName: typeGraph[tokens[pos]].typeName, name: tokens[pos] });
pos++;
} else {
const pos2 = pos; //cache the value to keep it from changing
//recurse
deferredCalls.push(async (result) => [tokens[pos2], await parseQuery(
handler,
tokens,
pos2,
superTypeGraph[typeGraph[tokens[pos2]].typeName],
superTypeGraph,
{ typeName: queryType, scalars: scalarFields, context: result }
)]);
pos = eatBlock(tokens, pos);
}
}
//eat the end bracket
pos++;
let results = handler[queryType](parent, scalarFields);
results = await Promise.all(results.map(async res => {
const tuples = await Promise.all(deferredCalls.map(async call => await call(res)));
tuples.forEach(tuple => res[tuple[0]] = tuple[1]);
return res;
}));
return results;
};
//utils
@@ -146,5 +210,17 @@ const checkAlphaNumeric = (str) => {
}
};
const eatBlock = (tokens, pos) => {
while (tokens[pos] && tokens[pos] != '}') {
if (tokens[pos] == '{') {
pos = eatBlock(tokens, pos+1);
} else {
pos++;
}
}
return pos;
};
//return
module.exports = main;