add python example

python-example/Pipfile

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+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+
+[dev-packages]
+
+[requires]
+python_version = "3.10"

python-example/README.md

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+# python example
+
+This example was adapted from [python-wasm-component](https://github.com/michelleN/python-wasm-component) repo. See repo for more information on how to build python component.

python-example/app.py

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+from http_app import exports
+
+from http_app.imports.types import (
+    IncomingRequest,
+    OutgoingResponse,
+    ResponseOutparam,
+    OutgoingBody,
+    Fields,
+    Ok,
+)
+
+
+class IncomingHandler(exports.IncomingHandler):
+    def handle(self, request: IncomingRequest, response_out: ResponseOutparam):
+        response = OutgoingResponse(200, Fields([("HELLO", b"WORLD")]))
+
+        response_body = response.write()
+
+        ResponseOutparam.set(response_out, Ok(response))
+
+        response_stream = response_body.write()
+        response_stream.blocking_write_and_flush(b"Hello from python!")
+        response_stream.drop()
+
+        OutgoingBody.finish(response_body, None)

python-example/componentize_py_runtime/__init__.py

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+
+from typing import List, Any
+
+def call_import(index: int, args: List[Any], result_count: int) -> List[Any]:
+    raise NotImplementedError

python-example/http_app/__init__.py

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+from typing import TypeVar, Generic, Union, Optional, Union, Protocol, Tuple, List, Any
+from enum import Flag, Enum, auto
+from dataclasses import dataclass
+from abc import abstractmethod
+import weakref
+
+from .types import Result, Ok, Err, Some
+import componentize_py_runtime
+
+
+
+class HttpApp(Protocol):
+    pass

python-example/http_app/exports/__init__.py

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+from typing import TypeVar, Generic, Union, Optional, Union, Protocol, Tuple, List, Any
+from enum import Flag, Enum, auto
+from dataclasses import dataclass
+from abc import abstractmethod
+import weakref
+
+from ..types import Result, Ok, Err, Some
+from ..imports import types
+
+class IncomingHandler(Protocol):
+
+    @abstractmethod
+    def handle(self, request: types.IncomingRequest, response_out: types.ResponseOutparam) -> None:
+        raise NotImplementedError
+
+

python-example/http_app/exports/incoming_handler.py

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+from typing import TypeVar, Generic, Union, Optional, Union, Protocol, Tuple, List, Any
+from enum import Flag, Enum, auto
+from dataclasses import dataclass
+from abc import abstractmethod
+import weakref
+
+from ..types import Result, Ok, Err, Some
+
+

python-example/http_app/imports/poll.py

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+"""
+A poll API intended to let users wait for I/O events on multiple handles
+at once.
+"""
+from typing import TypeVar, Generic, Union, Optional, Union, Protocol, Tuple, List, Any
+from enum import Flag, Enum, auto
+from dataclasses import dataclass
+from abc import abstractmethod
+import weakref
+
+from ..types import Result, Ok, Err, Some
+import componentize_py_runtime
+
+
+class Pollable:
+    """
+    A "pollable" handle.
+    """
+
+    def drop(self):
+        (_, func, args, _) = self.finalizer.detach()
+        self.handle = None
+        func(args[0], args[1])
+
+
+
+def poll_list(in_: List[Pollable]) -> List[int]:
+    """
+    Poll for completion on a set of pollables.
+
+    This function takes a list of pollables, which identify I/O sources of
+    interest, and waits until one or more of the events is ready for I/O.
+
+    The result `list<u32>` contains one or more indices of handles in the
+    argument list that is ready for I/O.
+
+    If the list contains more elements than can be indexed with a `u32`
+    value, this function traps.
+
+    A timeout can be implemented by adding a pollable from the
+    wasi-clocks API to the list.
+
+    This function does not return a `result`; polling in itself does not
+    do any I/O so it doesn't fail. If any of the I/O sources identified by
+    the pollables has an error, it is indicated by marking the source as
+    being reaedy for I/O.
+    """
+    result = componentize_py_runtime.call_import(1, [in_], 1)
+    return result[0]
+
+def poll_one(in_: Pollable) -> None:
+    """
+    Poll for completion on a single pollable.
+
+    This function is similar to `poll-list`, but operates on only a single
+    pollable. When it returns, the handle is ready for I/O.
+    """
+    result = componentize_py_runtime.call_import(2, [in_], 0)
+    return
+