UI and backend for basic OCR functionality

backend/main.py

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+import io
+from typing import Optional
+from fastapi import FastAPI, File, UploadFile, HTTPException, Depends
+from fastapi.middleware.cors import CORSMiddleware
+from pydantic import BaseModel
+from pypdf import PdfReader
+import pytesseract
+from PIL import Image
+
+app = FastAPI()
+
+# CORS configuration
+origins = [
+    "http://localhost",
+    "http://localhost:3000",
+    "http://localhost:5173", # Vite default
+    "http://localhost:4200", # Angular default
+    "http://127.0.0.1:4200",
+]
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=origins,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Models
+class LoginRequest(BaseModel):
+    username: str
+    password: str
+
+class LoginResponse(BaseModel):
+    token: str
+    message: str
+
+class NERResponse(BaseModel):
+    text: str
+
+# 1. User Login Module (Dummy)
+@app.post("/api/login", response_model=LoginResponse)
+async def login(request: LoginRequest):
+    if request.username == "admin" and request.password == "admin":
+        return LoginResponse(token="dummy-jwt-token-123", message="Login Successful")
+    raise HTTPException(status_code=401, detail="Invalid credentials")
+
+# 2. OCR Module
+def extract_text_from_pdf(file_bytes: bytes) -> str:
+    try:
+        reader = PdfReader(io.BytesIO(file_bytes))
+        text = ""
+        for page in reader.pages:
+            page_text = page.extract_text()
+            if page_text:
+                text += page_text + "\n"
+        return text.strip()
+    except Exception as e:
+        print(f"Error reading PDF: {e}")
+        return ""
+
+def extract_text_from_image(file_bytes: bytes) -> str:
+    try:
+        image = Image.open(io.BytesIO(file_bytes))
+        text = pytesseract.image_to_string(image)
+        return text.strip()
+    except Exception as e:
+        print(f"Error reading Image: {e}")
+        return ""
+
+from pdf2image import convert_from_bytes
+
+# ... (imports)
+
+@app.post("/api/ocr/extract", response_model=NERResponse)
+async def extract_text(file: UploadFile = File(...)):
+    content = await file.read()
+    filename = file.filename.lower()
+    
+    extracted_text = ""
+    
+    if filename.endswith(".pdf"):
+        # Try text extraction first
+        extracted_text = extract_text_from_pdf(content)
+        
+        # If text is empty, it might be a scanned PDF. 
+        if not extracted_text.strip():
+             try:
+                 images = convert_from_bytes(content)
+                 for i, image in enumerate(images):
+                     page_text = pytesseract.image_to_string(image)
+                     extracted_text += f"\n--- Page {i+1} ---\n{page_text}"
+             except Exception as e:
+                 extracted_text = f"Error processing Scanned PDF: {str(e)}\n\n(Hint: Ensure 'poppler' is installed on your system. Run 'brew install poppler')"
+
+    elif filename.endswith((".png", ".jpg", ".jpeg", ".tiff", ".bmp")):
+        extracted_text = extract_text_from_image(content)
+    else:
+        raise HTTPException(status_code=400, detail="Unsupported file type")
+    
+    return NERResponse(text=extracted_text)
+
+@app.get("/")
+def read_root():
+    return {"message": "OCR Backend API is running"}