D1 env access

[wanghaisheng]

from fastapi import FastAPI, Request
from pydantic import BaseModel

from js import Response


async def on_fetch(request, env):
    import asgi

    # print("here", env)
    return await asgi.fetch(app, request, env)


app = FastAPI()


@app.get("/")
async def root():
    return {"message": "Hello, World!"}


@app.get("/env")
async def root(req: Request):
    env = req.scope["env"]
    return {
        "message": "Here is an example of getting an environment variable: "
        + env.MESSAGE
    }


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


@app.post("/items/")
async def create_item(item: Item):
    return item


@app.put("/items/{item_id}")
async def create_item(item_id: int, item: Item, q: str | None = None):
    result = {"item_id": item_id, **item.dict()}
    if q:
        result.update({"q": q})
    return result


@app.get("/items/{item_id}")
async def read_item(item_id: int):
    return {"item_id": item_id}


@app.get("/tablelist")
async def fetch_tables(req: Request):
    env = req.scope["env"]

    # Query D1 - we'll list all tables in our database in this example
    results = await env.DB.prepare("PRAGMA table_list").all()
    # Return a JSON response
    return Response.json(results)

name = "hello-fastapi"
main = "src/worker.py"
compatibility_flags = ["python_workers"]
compatibility_date = "2023-12-18"

[vars]
MESSAGE = "This is an environment variable"


[[d1_databases]]
binding = "DB" # This will be how you refer to your database in your Worker
database_name = "jsonbase"
database_id = "69cf8448-d541-4bba-80ff-1264e73ccbde"

error

PythonError: Traceback (most recent call last):                                                                              
                                                                                                                                       
    File "/lib/python3.12/site-packages/fastapi/encoders.py", line 322, in jsonable_encoder                                            
      data = dict(obj)
             ^^^^^^^^^
  TypeError: 'pyodide.ffi.JsProxy' object is not iterable

  During handling of the above exception, another exception occurred:

  Traceback (most recent call last):
    File "/lib/python3.12/site-packages/fastapi/encoders.py", line 327, in jsonable_encoder
      data = vars(obj)
             ^^^^^^^^^
  TypeError: vars() argument must have __dict__ attribute

  The above exception was the direct cause of the following exception:

  Traceback (most recent call last):
    File "/session/metadata/worker.py", line 12, in on_fetch
      return await asgi.fetch(app, request, env)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/lib/python3.12/site-packages/asgi.py", line 188, in fetch
      result = await process_request(app, req, env)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/lib/python3.12/site-packages/asgi.py", line 130, in process_request
      await app(request_to_scope(req, env), receive, send)
    File "/lib/python3.12/site-packages/fastapi/applications.py", line 1054, in __call__
      await super().__call__(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/applications.py", line 123, in __call__
      await self.middleware_stack(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/middleware/errors.py", line 186, in __call__
      raise exc
    File "/lib/python3.12/site-packages/starlette/middleware/errors.py", line 164, in __call__
      await self.app(scope, receive, _send)
    File "/lib/python3.12/site-packages/starlette/middleware/exceptions.py", line 62, in __call__
      await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
      raise exc
    File "/lib/python3.12/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
      await app(scope, receive, sender)
    File "/lib/python3.12/site-packages/starlette/routing.py", line 758, in __call__
      await self.middleware_stack(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/routing.py", line 778, in app
      await route.handle(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/routing.py", line 299, in handle
      await self.app(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/routing.py", line 79, in app
      await wrap_app_handling_exceptions(app, request)(scope, receive, send)
    File "/lib/python3.12/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
      raise exc
    File "/lib/python3.12/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
      await app(scope, receive, sender)
    File "/lib/python3.12/site-packages/starlette/routing.py", line 74, in app
      response = await func(request)
                 ^^^^^^^^^^^^^^^^^^^
    File "/lib/python3.12/site-packages/fastapi/routing.py", line 296, in app
      content = await serialize_response(


X [ERROR] ^^^^^^^^^^^^^^^^^^^^^^^^^                                                                                                    
                                                                                                                                       
    File "/lib/python3.12/site-packages/fastapi/routing.py", line 180, in serialize_response                                           
      return jsonable_encoder(response_content)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "/lib/python3.12/site-packages/fastapi/encoders.py", line 330, in jsonable_encoder
      raise ValueError(errors) from e
  ValueError: [TypeError("'pyodide.ffi.JsProxy' object is not iterable"), TypeError('vars() argument
  must have __dict__ attribute')]

      at new_error (pyodide-internal:generated/pyodide.asm:20:9998)
      at [object Object]x16c818
      at [object Object]x17437e
      at _PyEM_TrampolineCall_JS (pyodide-internal:generated/pyodide.asm:20:120091)
      at [object Object]x1bf539
      at [object Object]x2c1c2d
      at [object Object]x206dd5
      at [object Object]x1bfc1b
      at [object Object]x1bff2a
      at [object Object]x1bffa8
      at [object Object]x29a879
      at [object Object]x2a0fde

[maxtheman]

@wanghaisheng I have run into this a few times now, it's a pyodide thing where the behavior isn't 100% intuitive.

For even somewhat complex dicts, JsProxy often fails to convert to JS without a more explicit instruction. In this case, I recommend using console.log from js import console to introspect the js object and then follow the to_js example in this doc to see how to provide more explicit object converters: https://developers.cloudflare.com/workers/languages/python/examples/

 to_js converts between Python dictionaries and JavaScript Objects
def to_js(obj):
   return _to_js(obj, dict_converter=Object.fromEntries)