More fixes to proxy (#1237)

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> [!IMPORTANT]
> Improved proxy handling in Rust and TypeScript by refining error
messages, URL construction, and request routing logic.
> 
>   - **Rust Proxy Handling**:
> - Improved error message in `to_base64_with_inferred_mime_type()` in
`mod.rs` to include `media_url.url`.
> - Refactored URL construction in `fetch_with_proxy()` in `mod.rs` to
use `new_proxy_url` variable.
>   - **TypeScript Proxy Middleware**:
> - Added logic in `extension.ts` to handle image GET requests by
setting path to empty string.
>     - Removed trailing slashes from paths in `extension.ts`.
> - Ensured `baml-original-url` header is used to route requests in
`extension.ts`.
>   - **Miscellaneous**:
> - Disabled ESLint rule `@typescript-eslint/no-misused-promises` in
`extension.ts`.
> 
> <sup>This description was created by </sup>[<img alt="Ellipsis"
src="https://img.shields.io/badge/Ellipsis-blue?color=175173">](https://www.ellipsis.dev?ref=BoundaryML%2Fbaml&utm_source=github&utm_medium=referral)<sup>
for e38f259. It will automatically
update as commits are pushed.</sup>


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Author: aaronvg

engine/baml-runtime/src/internal/llm_client/traits/mod.rs

@@ -635,9 +635,10 @@ async fn to_base64_with_inferred_mime_type(
         Ok((base64, mime_type))
     } else {
         Err(anyhow::anyhow!(
-            "Failed to fetch media: {}, {}",
+            "Failed to fetch media: {} {}, {}",
             response.status(),
-            response.text().await.unwrap_or_default()
+            media_url.url,
+            response.text().await.unwrap_or_default(),
         ))
     }
 }
@@ -664,15 +665,14 @@ async fn fetch_with_proxy(
     let client = reqwest::Client::new();
 
     let request = if let Some(proxy) = proxy_url {
-        client
-            .get(format!(
-                "{}{}",
-                proxy,
-                url.parse::<url::Url>()
-                    .map_err(|e| anyhow::anyhow!("Failed to parse URL: {}", e))?
-                    .path()
-            ))
-            .header("baml-original-url", url)
+        let new_proxy_url = format!(
+            "{}{}",
+            proxy,
+            url.parse::<url::Url>()
+                .map_err(|e| anyhow::anyhow!("Failed to parse URL: {}", e))?
+                .path()
+        );
+        client.get(new_proxy_url).header("baml-original-url", url)
     } else {
         client.get(url)
     };

typescript/vscode-ext/packages/vscode/src/extension.ts

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-misused-promises */
 import * as vscode from 'vscode'
 import axios from 'axios'
 import glooLens from './LanguageToBamlCodeLensProvider'
@@ -193,11 +194,21 @@ export function activate(context: vscode.ExtensionContext) {
     createProxyMiddleware({
       changeOrigin: true,
       pathRewrite: (path, req) => {
-        // Ensure the URL does not end with a slash
+        console.log('reqmethod', req.method)
+
+        // Remove the path in the case of images. Since we request things differently for image GET requests, where we add the url to localhost:4500/actual-url.png
+        // to prevent caching issues with Rust reqwest.
+        // But for normal completion POST requests, we always call localhost:4500.
+        // The original url is always in baml-original-url header.
+
+        // Check for file extensions and set path to empty string.
+        if (/\.[a-zA-Z0-9]+$/.test(path) && req.method === 'GET') {
+          return ''
+        }
+        // Remove trailing slash
         if (path.endsWith('/')) {
           return path.slice(0, -1)
         }
-        console.log('pathRewrite', path, req)
         return path
       },
       router: (req) => {
@@ -209,11 +220,14 @@ export function activate(context: vscode.ExtensionContext) {
           delete req.headers['origin']
 
           // Ensure the URL does not end with a slash
+          console.log('originalUrl1', originalUrl)
           if (originalUrl.endsWith('/')) {
             originalUrl = originalUrl.slice(0, -1)
           }
           console.log('returning original url', originalUrl)
-          return new URL(originalUrl).origin
+          // return new URL(originalUrl).toString()
+
+          return originalUrl
         } else {
           console.log('baml-original-url header is missing or invalid')
           throw new Error('baml-original-url header is missing or invalid')
@@ -222,33 +236,19 @@ export function activate(context: vscode.ExtensionContext) {
       logger: console,
       on: {
         proxyReq: (proxyReq, req, res) => {
-          console.log('proxying request')
-
-          try {
-            const bamlOriginalUrl = req.headers['baml-original-url']
-            if (bamlOriginalUrl === undefined) {
-              return
-            }
-            const targetUrl = new URL(bamlOriginalUrl)
-            // proxyReq.path = targetUrl.pathname
-            // proxyReq.p
-            // It is very important that we ONLY resolve against API_KEY_INJECTION_ALLOWED
-            // by using the URL origin! (i.e. NOT using str.startsWith - the latter can still
-            // leak API keys to malicious subdomains e.g. https://api.openai.com.evil.com)
-            // const headers = API_KEY_INJECTION_ALLOWED[proxyOrigin]
-            // if (headers === undefined) {
-            //   return
-            // }
-            // for (const [header, value] of Object.entries(headers)) {
-            //   proxyReq.setHeader(header, value)
-            // }
-            // proxyReq.removeHeader('origin')
-            // proxyReq.setHeader('Origin', targetUrl.origin)
-            console.info('Proxying an LLM request (to bypass CORS)', { proxyReq, req, res })
-          } catch (err) {
-            // This is not console.warn because it's not important
-            console.log('baml-original-url is not parsable', err)
-          }
+          // const bamlOriginalUrl = req.headers['baml-original-url']
+          // if (typeof bamlOriginalUrl === 'string') {
+          //   const targetUrl = new URL(bamlOriginalUrl)
+          //   // Copy all original headers except those we want to modify/remove
+          //   Object.entries(req.headers).forEach(([key, value]) => {
+          //     if (key !== 'host' && key !== 'origin' && key !== 'baml-original-url') {
+          //       proxyReq.setHeader(key, value)
+          //     }
+          //   })
+          //   // Set the correct origin and host headers
+          //   proxyReq.setHeader('origin', targetUrl.origin)
+          //   proxyReq.setHeader('host', targetUrl.host)
+          // }
         },
         proxyRes: (proxyRes, req, res) => {
           proxyRes.headers['Access-Control-Allow-Origin'] = '*'