Handle possible token expired errors

Signed-off-by: Tao He <sighingnow@gmail.com>

src/chatgpt-unofficial-proxy-api.ts

@@ -219,8 +219,11 @@ export class ChatGPTUnofficialProxyAPI {
               }
             } catch (err) {
               // ignore for now; there seem to be some non-json messages
-              // console.warn('fetchSSE onMessage unexpected error', err)
+              reject(err)
             }
+          },
+          onError: (err) => {
+            reject(err)
           }
         },
         this._fetch

src/fetch-sse.ts

@@ -6,10 +6,13 @@ import { streamAsyncIterable } from './stream-async-iterable'
 
 export async function fetchSSE(
   url: string,
-  options: Parameters<typeof fetch>[1] & { onMessage: (data: string) => void },
+  options: Parameters<typeof fetch>[1] & {
+    onMessage: (data: string) => void
+    onError?: (error: any) => void
+  },
   fetch: types.FetchFn = globalFetch
 ) {
-  const { onMessage, ...fetchOptions } = options
+  const { onMessage, onError, ...fetchOptions } = options
   const res = await fetch(url, fetchOptions)
   if (!res.ok) {
     let reason: string
@@ -33,6 +36,31 @@ export async function fetchSSE(
     }
   })
 
+  // check if the response is an error, if so, throw it
+  const feed = (chunk: string) => {
+    let response = null
+    try {
+      response = JSON.parse(chunk)
+    } catch {
+      /// ignore
+    }
+    if (response?.detail) {
+      if (response.detail.type === 'invalid_request_error') {
+        const msg = `ChatGPT error ${response.detail.message}: ${response.detail.code} (${response.detail.type})`
+        const error = new types.ChatGPTError(msg, { cause: response })
+        error.statusCode = response.detail.code
+        error.statusText = response.detail.message
+        if (onError) {
+          onError(error)
+        } else {
+          console.error(error)
+        }
+        return // don't feed to event parser
+      }
+    }
+    parser.feed(chunk)
+  }
+
   if (!res.body.getReader) {
     // Vercel polyfills `fetch` with `node-fetch`, which doesn't conform to
     // web standards, so this is a workaround...
@@ -45,13 +73,13 @@ export async function fetchSSE(
     body.on('readable', () => {
       let chunk: string | Buffer
       while (null !== (chunk = body.read())) {
-        parser.feed(chunk.toString())
+        feed(chunk.toString())
       }
     })
   } else {
     for await (const chunk of streamAsyncIterable(res.body)) {
       const str = new TextDecoder().decode(chunk)
-      parser.feed(str)
+      feed(str)
     }
   }
 }