Backend Requests Support via Requests-Compatible API Facade

Makefile

@@ -10,14 +10,16 @@ EXAMPLES_DIR := examples
 COMPUTE_WIT := wit/deps/fastly/compute.wit
 
 # Define all available examples (add new ones here)
-EXAMPLES := bottle-app flask-app game-of-life
+EXAMPLES := bottle-app flask-app backend-requests game-of-life
 
 # Default example for serve target
 EXAMPLE ?= bottle-app
 WASM_FILE := $(BUILD_DIR)/$(EXAMPLE).composed.wasm
 
 TARGET_WORLD := fastly:compute/service
 
+VICEROY ?= viceroy
+
 # Generate WASM file paths for all examples
 EXAMPLE_WASMS := $(foreach example,$(EXAMPLES),$(BUILD_DIR)/$(example).wasm)
 
@@ -57,7 +59,11 @@ serve: $(WASM_FILE)
 
 # Test all examples (requires all WASM files to be built)
 test: $(COMPOSED_WASMS)
-	uv run --extra test pytest
+	VICEROY=$(VICEROY) uv run --extra test pytest
+
+# Update snapshots for snapshot tests
+test-update-snapshots: $(COMPOSED_WASMS)
+	VICEROY=$(VICEROY) uv run --extra test pytest --snapshot-update
 
 # List available examples
 list-examples:
@@ -93,6 +99,7 @@ help:
 	@echo "  all                 Build all examples"
 	@echo "  serve [EXAMPLE=name] Serve example (default: $(EXAMPLE))"
 	@echo "  test                Run integration tests (builds all examples)"
+	@echo "  test-update-snapshots Update snapshot test baselines"
 	@echo "  build-all           Build all examples (alias for 'all')"
 	@echo "  list-examples       List available examples"
 	@echo "  clean               Clean build artifacts"
@@ -109,4 +116,4 @@ help:
 	@echo ""
 	@echo "Available examples: $(EXAMPLES)"
 
-.PHONY: all serve test list-examples build-all clean lint lint-fix format format-check help $(WASILESS_WASM)
+.PHONY: all serve test test-update-snapshots list-examples build-all clean lint lint-fix format format-check help $(WASILESS_WASM)

examples/backend-requests.py

@@ -0,0 +1,89 @@
+"""Example demonstrating interactions with backends via the requests facade"""
+
+import json
+import traceback
+import typing
+from typing import Any
+
+from bottle import Bottle, request
+
+import fastly_compute.requests as requests
+from fastly_compute.wsgi import WsgiHttpIncoming
+
+app = Bottle()
+
+
+def _map_error(e: Exception):
+    """Return a standardized error response.
+
+    Args:
+        e: The exception that occurred
+        demo: The demo/endpoint name for this error
+    """
+    return {
+        "error": repr(e),
+        "error_type": type(e).__name__,
+        "tb": traceback.format_exc(),
+    }
+
+
+def _proxy_request(method: str, url: str, **kwargs) -> dict[str, Any]:
+    try:
+        response = requests.request(method, url, **kwargs)
+    except Exception as e:
+        return _map_error(e)
+
+    return {
+        "method": method,
+        "url": url,
+        "fastly_backend": kwargs.get("fastly_backend"),
+        "status_code": response.status_code,
+        "success": response.ok,
+        "headers_count": len(response.headers),
+        "content_length": len(response.content),
+        "response_preview": response.text[:200] + "..."
+        if len(response.text) > 200
+        else response.text,
+    }
+
+
+@app.route("/proxy/<method>")
+def proxy(method: str):
+    """Proxy endpoint for testing; pass through parameters.
+
+    Don't deploy actual code that does this as it is likely
+    to be abused if allowed to hit unrestricted domains.
+    This proxy method is intended for testing use.
+    """
+    # Type checker doesn't quite understand bottle's DictProperty
+    # so we need to give it hints.
+    query = typing.cast(typing.Mapping[str, str], request.query)
+    headers_dict = typing.cast(typing.Mapping[str, str], request.headers)
+
+    url: str | None = query.get("url")
+    if not url:
+        return {"error": "url query parameter is required"}
+
+    backend = query.get("fastly_backend")
+    json_param = query.get("json")
+
+    # Reconstitute JSON parameter if present
+    json_data = None
+    if json_param:
+        try:
+            json_data = json.loads(json_param)
+        except json.JSONDecodeError as e:
+            return {"error": f"Invalid JSON in json parameter: {e}"}
+
+    headers = {}
+    for k, v in headers_dict.items():
+        if k.lower() != "host":
+            headers[k] = v
+
+    return _proxy_request(
+        method, url=url, fastly_backend=backend, json=json_data, headers=headers
+    )
+
+
+# Create the HTTP handler
+HttpIncoming = WsgiHttpIncoming(app)