feat: enhance Gemini API handling by extracting model from URL and enforcing model requirement

Author: cuipengfei

.gitignore

@@ -14,3 +14,5 @@ node_modules/
 dist/
 logs/gemini-debug.log
 logs/gemini-translation.log
+.env
+logs/gemini-errors.log

src/routes/messages/gemini-handler.ts

@@ -31,6 +31,13 @@ import {
   type GeminiResponse,
 } from "./gemini-types"
 
+// Helper function to extract model from URL path
+function extractModelFromUrl(url: string): string | undefined {
+  const path = new URL(url).pathname
+  const match = path.match(/^\/v1beta\/models\/([^:]+):/)
+  return match?.[1]
+}
+
 // Debug logging interface
 interface GeminiDebugLog {
   timestamp: string
@@ -280,7 +287,11 @@ function getErrorStatusAndMessage(error: unknown): {
 // Standard generation endpoint
 export async function handleGeminiGeneration(c: Context) {
   const endpoint = c.req.url
-  const model = c.req.param("model")
+  const model = extractModelFromUrl(endpoint)
+
+  if (!model) {
+    return c.json({ error: "Model name is required in URL path" }, 400)
+  }
 
   // IMMEDIATE DEBUG: Log that we entered this handler
   logGeminiDebug("handler_entry_GENERATION", endpoint, {
@@ -525,7 +536,11 @@ async function ensureCompleteStream(
 // Streaming generation endpoint
 export async function handleGeminiStreamGeneration(c: Context) {
   const endpoint = c.req.url
-  const model = c.req.param("model")
+  const model = extractModelFromUrl(endpoint)
+
+  if (!model) {
+    return c.json({ error: "Model name is required in URL path" }, 400)
+  }
 
   logGeminiDebug("handler_entry", endpoint, {
     data: {
@@ -581,7 +596,11 @@ export async function handleGeminiStreamGeneration(c: Context) {
 // Token counting endpoint
 export async function handleGeminiCountTokens(c: Context) {
   const endpoint = c.req.url
-  const model = c.req.param("model")
+  const model = extractModelFromUrl(endpoint)
+
+  if (!model) {
+    return c.json({ error: "Model name is required in URL path" }, 400)
+  }
 
   // IMMEDIATE DEBUG: Log that we entered this handler
   logGeminiDebug("handler_entry_TOKENS", endpoint, {

src/routes/messages/gemini-translation.ts

@@ -26,10 +26,10 @@ import {
 
 export function translateGeminiToOpenAINonStream(
   payload: GeminiRequest,
-  model?: string,
+  model: string,
 ): ChatCompletionsPayload {
   return {
-    model: model || "claude-sonnet-4", // Use provided model or default
+    model, // Always use the model from the URL
     messages: translateGeminiContentsToOpenAI(
       payload.contents,
       payload.systemInstruction,
@@ -46,10 +46,10 @@ export function translateGeminiToOpenAINonStream(
 
 export function translateGeminiToOpenAIStream(
   payload: GeminiRequest,
-  model?: string,
+  model: string,
 ): ChatCompletionsPayload {
   const result = {
-    model: model || "claude-sonnet-4", // Use provided model or default
+    model, // Always use the model from the URL
     messages: translateGeminiContentsToOpenAI(
       payload.contents,
       payload.systemInstruction,
@@ -417,10 +417,10 @@ export function translateOpenAIChunkToGemini(chunk: ChatCompletionChunk): {
 
 export function translateGeminiCountTokensToOpenAI(
   request: GeminiCountTokensRequest,
-  model?: string,
+  model: string,
 ): ChatCompletionsPayload {
   return {
-    model: model || "claude-sonnet-4",
+    model,
     messages: translateGeminiContentsToOpenAI(
       request.contents,
       request.systemInstruction,