Add SDK version and headers to client requests

- Injected `wsn` and `User-Agent` headers into all client requests.
- Dynamically set SDK version using `importlib.metadata.version`.
- Added test cases to validate the headers in both synchronous and
  asynchronous clients.

Assisted-by: Codex

Author: datalogics-kam

src/pdfrest/client.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+import importlib.metadata
 import json
 import os
 import uuid
@@ -337,7 +338,12 @@ def __init__(
         if resolved_api_key is not None:
             self._validate_pdfrest_api_key(resolved_api_key, resolved_base_url)
 
-        default_headers: dict[str, str] = {"Accept": "application/json"}
+        version = importlib.metadata.version("pdfrest")
+        default_headers: dict[str, str] = {
+            "Accept": "application/json",
+            "wsn": "pdfrest-python",
+            "User-Agent": f"pdfrest-python-sdk/{version}",
+        }
         if resolved_api_key is not None:
             default_headers[API_KEY_HEADER_NAME] = resolved_api_key
         if headers:

tests/test_client.py

@@ -14,6 +14,7 @@
     PdfRestConfigurationError,
     PdfRestTimeoutError,
     UpResponse,
+    client as client_module,
 )
 
 VALID_API_KEY = "12345678-1234-1234-1234-123456789abc"
@@ -61,6 +62,39 @@ def handler(request: httpx.Request) -> httpx.Response:
     assert response.product == "pdfRest API Toolkit"
 
 
+def test_client_sets_sdk_headers(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("PDFREST_API_KEY", VALID_API_KEY)
+    monkeypatch.setattr(client_module.importlib.metadata, "version", lambda _: "1.2.3")
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        assert request.headers["wsn"] == "pdfrest-python"
+        assert request.headers["User-Agent"] == "pdfrest-python-sdk/1.2.3"
+        assert request.headers["Accept"] == "application/json"
+        return httpx.Response(200, json=_build_up_response())
+
+    transport = httpx.MockTransport(handler)
+    with PdfRestClient(api_key=VALID_API_KEY, transport=transport) as client:
+        client.up()
+
+
+@pytest.mark.asyncio
+async def test_async_client_sets_sdk_headers(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv("PDFREST_API_KEY", ASYNC_API_KEY)
+    monkeypatch.setattr(client_module.importlib.metadata, "version", lambda _: "4.5.6")
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        assert request.headers["wsn"] == "pdfrest-python"
+        assert request.headers["User-Agent"] == "pdfrest-python-sdk/4.5.6"
+        assert request.headers["Accept"] == "application/json"
+        return httpx.Response(200, json=_build_up_response())
+
+    transport = httpx.MockTransport(handler)
+    async with AsyncPdfRestClient(api_key=ASYNC_API_KEY, transport=transport) as client:
+        await client.up()
+
+
 def test_missing_api_key_raises(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.delenv("PDFREST_API_KEY", raising=False)