Populate php://input and other streams – JSON POST requests are broken

[adamziel]

In PHP, parsing JSON data from POST is often handled with file_get_contents( 'php://input' );. That stream is read-only and can't be pre-populated by a PHP code in php-server.ts. Instead, it must happen somewhere in the C code in php_wasm.c.

For example, submitting a POST request with {"foo": "bar"} as body and a content-type: application/json should yield bar in the following code:

$raw_request_body = file_get_contents('php://input');
echo json_decode($raw_request_body)['foo'];

At the moment, it does not.

[adamziel]

The trick is:

int EMSCRIPTEN_KEEPALIVE phpwasm_init_context()
{
	putenv("USE_ZEND_ALLOC=0");

	SG(request_info).request_method = "POST";
	SG(request_info).content_type = "application/json";
	php_embed_module.read_post = *php__wasm_read_post;
	return php_embed_init(0, NULL);
}

static int php__wasm_read_post(char *buffer, uint count_bytes)
{
	sprintf (buffer, "{\"test\": \"foo\"}");
	return 15;
}

[adamziel]

As of #107, php://input is populated with the request body.

High-level API:

const response = php.run({
	method: 'POST',
	body: '{"foo": "bar"}',
	code: `<?php echo file_get_contents('php://input');`,
});
const bodyText = new TextDecoder().decode(response.body);
expect(bodyText).toEqual('{"foo": "bar"}');

Low-level API:

this.#Runtime.ccall('wasm_set_request_body', null, [STR], ['{"test": "foo"}']);
this.#Runtime.ccall('wasm_set_request_method', null, [STR], ['POST']);
this.#Runtime.ccall('wasm_set_content_type', null, [STR], ["application/x-www-form-urlencoded"]);
this.#Runtime.ccall('wasm_set_php_code', null, [STR], ['<?php echo file_get_contents("php://input"); ']);
this.#Runtime.ccall('wasm_sapi_handle_request', NUM, [], []);
console.log(this.readFileAsBuffer('/tmp/stdout'));
// {"test": "foo"}