Fix widget API 500 error and login 405 error

- Add public-proxy utility for URL normalization and response handling
- Fix widget API proxy to handle URLs without protocol and non-JSON responses
- Fix login form 405 error by adding action='#' and stopPropagation
- Improve error handling in public API routes

Author: StephaneWamba

frontend/app/api/public/agents/[id]/route.ts

@@ -5,6 +5,7 @@
 
 import { NextRequest, NextResponse } from 'next/server'
 import { logger } from '@/lib/utils/logger'
+import { normalizeServiceUrl, handleResponse } from '@/lib/api/public-proxy'
 
 const AGENT_SERVICE_URL = process.env.AGENT_SERVICE_URL || 'http://localhost:4002'
 
@@ -28,23 +29,41 @@ export async function GET(request: NextRequest,
     id = resolvedParams.id
     const authHeader = request.headers.get('authorization')
 
-    // Proxy to agent service
-    const response = await fetch(`${AGENT_SERVICE_URL}/api/public/agents/${id}`, {
+    // Normalize service URL (ensure protocol)
+    const serviceUrl = normalizeServiceUrl(AGENT_SERVICE_URL)
+    const targetUrl = `${serviceUrl}/api/public/agents/${id}`
+    
+    logger.debug('Proxying public agent request', { targetUrl, agentId: id, hasAuth: !!authHeader })
+
+    const response = await fetch(targetUrl, {
       method: 'GET',
       headers: {
         ...(authHeader ? { 'Authorization': authHeader } : {}),
         'Content-Type': 'application/json',
       },
     })
 
-    const data = await response.json()
+    // Handle response (JSON or error)
+    let data: unknown
+    try {
+      data = await handleResponse(response, { agentId: id, endpoint: 'getAgent' })
+    } catch (error) {
+      return NextResponse.json(
+        { error: 'Invalid response from service', details: error instanceof Error ? error.message : String(error) },
+        { status: response.status || 500, headers: corsHeaders }
+      )
+    }
 
     return NextResponse.json(data, {
       status: response.status,
       headers: corsHeaders,
     })
   } catch (error) {
-    logger.error('Public API error proxying agent', { error, agentId: id })
+    logger.error('Public API error proxying agent', { 
+      error: error instanceof Error ? error.message : String(error),
+      stack: error instanceof Error ? error.stack : undefined,
+      agentId: id 
+    })
     return NextResponse.json(
       { error: 'Internal server error', details: error instanceof Error ? error.message : String(error) },
       { status: 500, headers: corsHeaders }

frontend/components/auth/sign-in-form.tsx

@@ -1,6 +1,6 @@
 'use client'
 
-import { useState, useEffect } from 'react'
+import { useState, useEffect, useTransition } from 'react'
 import { useRouter, useSearchParams } from 'next/navigation'
 import { useForm } from 'react-hook-form'
 import { zodResolver } from '@hookform/resolvers/zod'
@@ -22,6 +22,7 @@ import { toast } from 'sonner'
 export function SignInForm() {
   const router = useRouter()
   const searchParams = useSearchParams()
+  const [isPending, startTransition] = useTransition()
   const [isLoading, setIsLoading] = useState(false)
   const [isOAuthLoading, setIsOAuthLoading] = useState<string | null>(null)
   const redirectTo = searchParams?.get('redirect') || '/dashboard'
@@ -77,7 +78,15 @@ export function SignInForm() {
   return (
     <div className="space-y-6">
       <Form {...form}>
-        <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-4">
+        <form 
+          action="#"
+          onSubmit={(e) => {
+            e.preventDefault()
+            e.stopPropagation()
+            form.handleSubmit(onSubmit)(e)
+          }} 
+          className="space-y-4"
+        >
           <FormField
             control={form.control}
             name="email"
@@ -116,8 +125,8 @@ export function SignInForm() {
             )}
           />
 
-          <Button type="submit" className="w-full" disabled={isLoading}>
-            {isLoading && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
+          <Button type="submit" className="w-full" disabled={isLoading || isPending}>
+            {(isLoading || isPending) && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
             Sign in
           </Button>
         </form>

frontend/lib/api/public-proxy.ts

@@ -0,0 +1,40 @@
+/**
+ * Public API Proxy Utility
+ * 
+ * Helper functions for proxying public API requests to backend services.
+ * Handles URL protocol normalization and error handling.
+ */
+
+import { logger } from '@/lib/utils/logger'
+
+/**
+ * Normalize service URL by ensuring it has a protocol
+ */
+export function normalizeServiceUrl(url: string): string {
+  let normalized = url.replace(/\/$/, '') // Remove trailing slash
+  if (!normalized.startsWith('http://') && !normalized.startsWith('https://')) {
+    normalized = `https://${normalized}`
+  }
+  return normalized
+}
+
+/**
+ * Handle non-JSON responses from backend services
+ */
+export async function handleResponse(response: Response, context: { agentId?: string; endpoint?: string }) {
+  const contentType = response.headers.get('content-type')
+  
+  if (contentType?.includes('application/json')) {
+    return await response.json()
+  } else {
+    const text = await response.text()
+    logger.error('Non-JSON response from backend service', {
+      status: response.status,
+      contentType,
+      text: text.substring(0, 200),
+      ...context,
+    })
+    throw new Error(`Invalid response from service: ${text.substring(0, 200)}`)
+  }
+}
+