graphql-helix
Version:
A highly evolved GraphQL HTTP Server 🧬
56 lines (55 loc) • 2.27 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.getRankedResponseProtocols = void 0;
function normalizeValue(str) {
return str.split(";")[0].trim();
}
/**
* parses an accept header string '"application/json, text/event-stream"' into an array of strings '["application/json", "text/event-stream"]'
* @param acceptHeader accept header string as sent by client
* @returns
*/
function parseAcceptHeader(acceptHeader) {
return acceptHeader.split(",").map(normalizeValue);
}
/**
* Returns a map of ranked protocols which can be used for determining teh protocol for sending a response to the client.
* @param acceptHeader accept header string as sent by client
* @param contentTypeHeader content-type header string as sent by client
*/
function getRankedResponseProtocols(acceptHeader, contentTypeHeader) {
const rankedProtocols = {
"application/graphql+json": -1,
"application/json": -1 /* LEGACY */,
"text/event-stream": -1,
"multipart/mixed": -1,
};
/**
* In case no acceptHeader has been sent by the client, the response protocol is determined by trying to mirror the incoming content-type.
* This works for 'application/graphql+json' and 'application/json'.
*/
if (typeof acceptHeader !== "string") {
// if no accept is provided we rank up the content-type
if (typeof contentTypeHeader === "string") {
const normalizedContentType = normalizeValue(contentTypeHeader);
if (normalizedContentType in rankedProtocols) {
rankedProtocols[normalizedContentType]++;
}
}
return rankedProtocols;
}
/**
* In case no acceptHeader has been sent by the client, we need to parse it and then create ranking of what suits the client best.
* See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept
*/
const supportedProtocols = parseAcceptHeader(acceptHeader);
let index = 0;
for (const protocol of supportedProtocols) {
if (protocol in rankedProtocols) {
rankedProtocols[protocol] = index;
index++;
}
}
return rankedProtocols;
}
exports.getRankedResponseProtocols = getRankedResponseProtocols;