Hugging Face's logo

Spaces:
aukaru
/
344
Paused

App Files Community
344 / src /proxy /middleware /request /proxy-req-manager.ts
aukaru's picture
aukaru
Upload 236 files
5c5b371 verified
Raw History Blame Contribute Delete
3.41 kB
import { Request } from "express";
import { Key } from "../../../shared/key-management";
import { assertNever } from "../../../shared/utils";
/**
* Represents a change to the request that will be reverted if the request
* fails.
*/
interface ProxyReqMutation {
target: "header" | "path" | "body" | "api-key" | "signed-request";
key?: string;
originalValue: any | undefined;
}
/**
* Manages a request's headers, body, and path, allowing them to be modified
* before the request is proxied and automatically reverted if the request
* needs to be retried.
*/
export class ProxyReqManager {
private req: Request;
private mutations: ProxyReqMutation[] = [];
/**
* A read-only proxy of the request object. Avoid changing any properties
* here as they will persist across retries.
*/
public readonly request: Readonly<Request>;
constructor(req: Request) {
this.req = req;
this.request = new Proxy(req, {
get: (target, prop) => {
if (typeof prop === "string") return target[prop as keyof Request];
return undefined;
},
});
}
setHeader(name: string, newValue: string): void {
const originalValue = this.req.get(name);
this.mutations.push({ target: "header", key: name, originalValue });
this.req.headers[name.toLowerCase()] = newValue;
}
removeHeader(name: string): void {
const originalValue = this.req.get(name);
this.mutations.push({ target: "header", key: name, originalValue });
delete this.req.headers[name.toLowerCase()];
}
setBody(newBody: any): void {
const originalValue = this.req.body;
this.mutations.push({ target: "body", key: "body", originalValue });
this.req.body = newBody;
}
setKey(newKey: Key): void {
const originalValue = this.req.key;
this.mutations.push({ target: "api-key", key: "key", originalValue });
this.req.key = newKey;
}
setPath(newPath: string): void {
const originalValue = this.req.path;
this.mutations.push({ target: "path", key: "path", originalValue });
this.req.url = newPath;
}
setSignedRequest(newSignedRequest: typeof this.req.signedRequest): void {
const originalValue = this.req.signedRequest;
this.mutations.push({ target: "signed-request", key: "signedRequest", originalValue });
this.req.signedRequest = newSignedRequest;
}
hasChanged(): boolean {
return this.mutations.length > 0;
}
revert(): void {
for (const mutation of this.mutations.reverse()) {
switch (mutation.target) {
case "header":
if (mutation.originalValue === undefined) {
delete this.req.headers[mutation.key!.toLowerCase()];
continue;
} else {
this.req.headers[mutation.key!.toLowerCase()] =
mutation.originalValue;
}
break;
case "path":
this.req.url = mutation.originalValue;
break;
case "body":
this.req.body = mutation.originalValue;
break;
case "api-key":
// We don't reset the key here because it's not a property of the
// inbound request, so we'd only ever be reverting it to null.
break;
case "signed-request":
this.req.signedRequest = mutation.originalValue;
break;
default:
assertNever(mutation.target);
}
}
this.mutations = [];
}
}