correctly decompresses gzip/deflate payloads

package-lock.json

@@ -14,7 +14,8 @@
         "express": "^4.18.2",
         "http-proxy-middleware": "^3.0.0-beta.1",
         "pino-http": "^8.3.3",
-        "showdown": "^2.1.0"
+        "showdown": "^2.1.0",
+        "zlib": "^1.0.5"
       },
       "devDependencies": {
         "@types/cors": "^2.8.13",
@@ -1624,6 +1625,15 @@
       "engines": {
         "node": ">=6"
       }
+    },
+    "node_modules/zlib": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/zlib/-/zlib-1.0.5.tgz",
+      "integrity": "sha512-40fpE2II+Cd3k8HWTWONfeKE2jL+P42iWJ1zzps5W51qcTsOUKM5Q5m2PFb0CLxlmFAaUuUdJGc3OfZy947v0w==",
+      "hasInstallScript": true,
+      "engines": {
+        "node": ">=0.2.0"
+      }
     }
   }
 }

package.json

@@ -15,7 +15,8 @@
     "express": "^4.18.2",
     "http-proxy-middleware": "^3.0.0-beta.1",
     "pino-http": "^8.3.3",
-    "showdown": "^2.1.0"
+    "showdown": "^2.1.0",
+    "zlib": "^1.0.5"
   },
   "devDependencies": {
     "@types/cors": "^2.8.13",

src/proxy/common.ts

@@ -1,5 +1,7 @@
 import { Request, Response } from "express";
 import * as http from "http";
+import util from "util";
+import zlib from "zlib";
 import * as httpProxy from "http-proxy";
 import { logger } from "../logger";
 import { keys } from "../keys";
@@ -20,9 +22,20 @@ export const handleDownstreamErrors = (
       return resolve();
     }
 
-    let body = "";
-    proxyRes.on("data", (chunk) => (body += chunk));
-    proxyRes.on("end", () => {
+    let chunks: Buffer[] = [];
+    proxyRes.on("data", (chunk) => chunks.push(chunk));
+    proxyRes.on("end", async () => {
+      let body = Buffer.concat(chunks);
+      const contentEncoding = proxyRes.headers["content-encoding"];
+
+      if (contentEncoding === "gzip") {
+        body = await util.promisify(zlib.gunzip)(body);
+      } else if (contentEncoding === "deflate") {
+        body = await util.promisify(zlib.inflate)(body);
+      }
+
+      const bodyString = body.toString();
+
       let errorPayload: any = {
         error: "Proxy couldn't parse error from OpenAI",
       };
@@ -30,14 +43,14 @@ export const handleDownstreamErrors = (
         ? "You can try again to get a different key."
         : "There are no more keys available.";
       try {
-        errorPayload = JSON.parse(body);
+        errorPayload = JSON.parse(bodyString);
       } catch (parseError: any) {
         const errorObject = {
           error: parseError.message,
-          trace:  parseError.stack,
-          body: body,
-        }
-        
+          trace: parseError.stack,
+          body: bodyString,
+        };
+
         logger.error(errorObject, "Unparseable error from OpenAI");
         res.json(errorObject);
         return reject(parseError.message);

src/proxy/kobold.ts

@@ -4,6 +4,8 @@ requests to OpenAI API equivalents. */
 import { Request, Response, Router } from "express";
 import http from "http";
 import { createProxyMiddleware } from "http-proxy-middleware";
+import util from "util";
+import zlib from "zlib";
 import { logger } from "../logger";
 import {
   copyHttpHeaders,
@@ -17,8 +19,8 @@ import {
   finalizeBody,
   languageFilter,
   limitOutputTokens,
+  transformKoboldPayload,
 } from "./rewriters";
-import { transformKoboldPayload } from "./rewriters/transform-kobold-payload";
 
 export const handleModelRequest = (_req: Request, res: Response) => {
   res.status(200).json({ result: "Connected to OpenAI reverse proxy" });
@@ -68,10 +70,20 @@ const handleProxiedResponse = async (
 
   // For Kobold we need to consume the response body to turn it into a KoboldAI
   // response payload.
-  let body = "";
-  proxyRes.on("data", (chunk) => (body += chunk));
-  proxyRes.on("end", () => {
-    const response = JSON.parse(body);
+  let chunks: Buffer[] = [];
+  proxyRes.on("data", (chunk) => chunks.push(chunk));
+  proxyRes.on("end", async () => {
+    let body = Buffer.concat(chunks);
+    const contentEncoding = proxyRes.headers["content-encoding"];
+
+    if (contentEncoding === "gzip") {
+      body = await util.promisify(zlib.gunzip)(body);
+    } else if (contentEncoding === "deflate") {
+      body = await util.promisify(zlib.inflate)(body);
+    }
+
+    const response = JSON.parse(body.toString());
+
     const koboldResponse = {
       results: [{ text: response.choices[0].message.content }],
     };

src/proxy/rewriters/index.ts

@@ -7,6 +7,7 @@ export { languageFilter } from "./language-filter";
 export { disableStream } from "./disable-stream";
 export { limitOutputTokens } from "./limit-output-tokens";
 export { finalizeBody } from "./finalize-body";
+export { transformKoboldPayload } from "./transform-kobold-payload";
 
 export type ExpressHttpProxyReqCallback = ProxyReqCallback<
   ClientRequest,