Google Books API Integration

# Google Books API Integration

This PR adds two MCP tools for integration with Google Books API.
Those tools can be tested with Gradio UI in two dedicated tabs:

* __Google Books - Search__: search books with filters (title, author, isbn, genre) and return a json with the list of books info. Each book has only some basic information ('lite' version of the book), but full information are available with the other tool described below.
Response object looks like this:
```json
{
"kind": "books#volumes",
"totalItems": 1000000,
"items": [
{
"kind": "books#volume",
"id": "pZ49u0fSuGsC",
"etag": "kCfPFbplXAM",
"selfLink": "https://www.googleapis.com/books/v1/volumes/pZ49u0fSuGsC",
"volumeInfo": {
"title": "Professional Test Driven Development with C#",
"subtitle": "Developing Real World Applications with TDD",
"authors": [
"James Bender",
"Jeff McWherter"
],
...
},
...
},
...
]
}
```

* __Google Books - Get Book By Id__: this tool can be useful to retrieve a book by its Google Books ID, returning a json with all information about the book.
In case of success, the returned json looks like a single item from the previous tool's response object (plus some additional fields).
In case of non-existent book, the returned json looks like this:

```json
{
"error": {
"code": 404,
"message": "The volume ID could not be found.",
"errors": [
{
"message": "The volume ID could not be found.",
"domain": "global",
"reason": "notFound"
}
]
}
}
```

app.py

@@ -1,4 +1,5 @@
 import gradio as gr
+import json
 import requests
 
 import flux
@@ -70,7 +71,56 @@ def calculate(n1, op, n2):
     if op == "*": return str(n1 * n2)
     if op == "/" and n2 != 0: return str(n1 / n2)
     return "Error"
-    
+
+
+BASE_GOOGLE_BOOKS_VOLUMES_API = "https://www.googleapis.com/books/v1/volumes"
+
+def get_google_book_filtered(title="", author="", genre="", isbn=""):
+    """
+    Get a filtered list of books from Google Books API.
+    It can be filtered by title, author, genre, and ISBN.
+    Results are ordered by relevance to the query.
+    Only a subset of the volume info is included.
+    Only 10 results are returned.
+    Args:
+        title: str - title of the book
+        author: str - author of the book
+        genre: str - genre of the book
+        isbn: str - ISBN of the book
+    Returns:
+        list - list of books
+    """
+    query = "q="
+    if title:
+        query += f"intitle:{title}"
+    if author:
+        query += f"+inauthor:{author}"
+    if genre:
+        query += f"+subject:{genre}"
+    if isbn:
+        query += f"+isbn:{isbn}"
+
+    if query != "q=":
+        url = f"{BASE_GOOGLE_BOOKS_VOLUMES_API}?{query}"
+        url += "&orderBy=relevance"
+        url += "&maxResults=10"
+        url += "&projection=lite"  # only include a subset of the volume info
+
+        json_res = requests.get(url).json()
+        return json.dumps(json_res, indent=2)
+
+def get_google_books_book_by_id(book_id):
+    """
+    Get a book from Google Books API by its ID.
+    Args:
+        book_id: str - ID of the book
+    Returns:
+        dict - book
+    """
+    url = f"{BASE_GOOGLE_BOOKS_VOLUMES_API}/{book_id}?projection=full"
+
+    json_res = requests.get(url).json()
+    return json.dumps(json_res, indent=2)
 
 print(f"DEBUG: Gradio version={gr. __version__}")
 
@@ -80,7 +130,7 @@ with gr.Blocks() as demo:
 
                 ### Built from the ground up for LLMs
 
-                This app provides a simple calculator, a dad joke generator, a greeting function, and an image generation feature.
+                This app provides a simple calculator, a dad joke generator, a greeting function, an image generation feature and a Google Books API integration.
 
                 Read the [project documentation](https://huggingface.co/spaces/Agents-MCP-Hackathon/simple-calculator/blob/main/README.md) to understand its background and motivations.
 
@@ -135,6 +185,54 @@ with gr.Blocks() as demo:
             outputs=img_output,
             api_name="generate_image")
 
+    tab_GB_search = gr.Tab("Google Books - Search")
+    with tab_GB_search:
+        with gr.Row():
+            title_textbox = gr.Textbox(
+                label="Title",
+                placeholder="Filter by title",
+            )
+            author_textbox = gr.Textbox(
+                label="Author",
+                placeholder="Filter by author",
+            )
+        with gr.Row():
+            genre_textbox = gr.Textbox(
+                label="Genre",
+                placeholder="Filter by genre",
+            )
+            isbn_textbox = gr.Textbox(
+                label="ISBN",
+                placeholder="Filter by ISBN",
+            )
+        with gr.Row():
+            search_btn = gr.Button("Search Books")
+        with gr.Row():
+            output_books_box = gr.Textbox(label="Results")
+        search_btn.click(
+            fn=get_google_book_filtered,
+            inputs=[title_textbox, author_textbox, genre_textbox, isbn_textbox],
+            outputs=output_books_box,
+            api_name="google_books_search",
+        )
+
+    tab_GB_get_by_id = gr.Tab("Google Books - Get Book By ID")
+    with tab_GB_get_by_id:
+        with gr.Row():
+            id_textbox = gr.Textbox(
+                label="ID",
+                placeholder="Book ID",
+            )
+            search_btn = gr.Button("Get Book")
+        with gr.Row():
+            output_book_box = gr.Textbox(label="Results")
+        search_btn.click(
+            fn=get_google_books_book_by_id,
+            inputs=[id_textbox],
+            outputs=output_book_box,
+            api_name="google_books_get_by_id",
+        )
+
 demo.launch(
     mcp_server=True,
     share=True,