Add a wasi-http echo-request component in C

This adds a wasi-http version of luw-echo-request.c[0]

This works under the wasmtime v15 CLI serve command.

e.g

  $ ~/src/c/wasm/wasmtime-v15.0.0-x86_64-linux/wasmtime serve c/wasi-http/echo-request/component.wasm
  Serving HTTP on http://0.0.0.0:8080/

  $ curl localhost:8080/hello
  *** Welcome to WebAssembly with wasi-http / C ***

  [Request Info]
  REQUEST_PATH = /hello
  METHOD       = GET
  QUERY        =

  [Request Headers]
  host = localhost:8080
  user-agent = curl/8.2.1
  accept = */*

[0]: <https://github.com/nginx/unit-wasm/blob/main/examples/c/luw-echo-request.c>

Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

1 files changed, 173 insertions, 0 deletions

diff --git a/c/wasi-http/echo-request/component.c b/c/wasi-http/echo-request/component.c
new file mode 100644
index 0000000..cecf390
--- /dev/null
+++ b/c/wasi-http/echo-request/component.c
@@ -0,0 +1,173 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+/*
+ * component.c - Example of writing a wasi-http Wasm component
+ *
+ * Copyright (C) Andrew Clayton
+ * Copyright (C) F5, Inc.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "proxy.h"
+
+#define ex(...) \
+	do { \
+		printf(__VA_ARGS__); \
+		exit(EXIT_FAILURE); \
+	} while (0);
+
+static const struct {
+	const char *method;
+} http_method_map[] = {
+	[WASI_HTTP_TYPES_METHOD_GET]	 = { "GET"     },
+	[WASI_HTTP_TYPES_METHOD_HEAD]	 = { "HEAD"    },
+	[WASI_HTTP_TYPES_METHOD_POST]    = { "POST"    },
+	[WASI_HTTP_TYPES_METHOD_PUT]	 = { "PUT"     },
+	[WASI_HTTP_TYPES_METHOD_DELETE]	 = { "DELETE"  },
+	[WASI_HTTP_TYPES_METHOD_CONNECT] = { "CONNECT" },
+	[WASI_HTTP_TYPES_METHOD_OPTIONS] = { "OPTIONS" },
+	[WASI_HTTP_TYPES_METHOD_TRACE]	 = { "TRACE"   },
+	[WASI_HTTP_TYPES_METHOD_PATCH]   = { "PATCH"   },
+	[WASI_HTTP_TYPES_METHOD_OTHER]	 = { "OTHER"   }
+};
+
+void exports_wasi_http_incoming_handler_handle(
+	exports_wasi_http_incoming_handler_own_incoming_request_t request,
+	exports_wasi_http_incoming_handler_own_response_outparam_t response_out)
+{
+	bool ok;
+	FILE *out;
+	size_t size;
+	char *out_ptr;
+	char *ptr;
+	char clen[32];
+	wasi_http_types_borrow_incoming_request_t b_req;
+	wasi_http_types_own_headers_t hdrs;
+	wasi_http_types_borrow_fields_t b_hdrs;
+	wasi_http_types_own_incoming_body_t r_body;
+	wasi_http_types_borrow_incoming_body_t b_r_body;
+	wasi_http_types_own_outgoing_response_t resp;
+	wasi_http_types_borrow_outgoing_response_t b_resp;
+	wasi_http_types_own_fields_t fields;
+	wasi_http_types_borrow_fields_t b_fields;
+	wasi_http_types_result_own_outgoing_response_error_code_t rerr = { };
+	wasi_http_types_own_outgoing_body_t body;
+	wasi_http_types_borrow_outgoing_body_t b_body;
+	wasi_io_streams_own_output_stream_t out_stream;
+	wasi_io_streams_borrow_output_stream_t b_out_stream;
+	wasi_io_streams_list_u8_t stream_data;
+	wasi_io_streams_stream_error_t stream_err;
+	wasi_http_types_error_code_t http_err;
+	wasi_http_types_header_error_t hdr_err;
+	wasi_http_types_field_key_t key;
+	wasi_http_types_field_value_t value;
+	wasi_http_types_method_t method;
+	wasi_http_types_list_tuple2_field_key_field_value_t fvk;
+	wasi_http_types_own_input_stream_t in_stream;
+	wasi_io_streams_borrow_input_stream_t b_in_stream;
+	wasi_io_streams_list_u8_t data;
+	wasi_io_streams_stream_error_t in_stream_err;
+	proxy_string_t prstr;
+
+	b_req = wasi_http_types_borrow_incoming_request(request);
+
+	out = open_memstream(&out_ptr, &size);
+
+#define BUF_ADD(fmt, ...) \
+	fprintf(out, fmt, ##__VA_ARGS__);
+
+	BUF_ADD("*** Welcome to WebAssembly with wasi-http / C ***\n\n");
+
+	BUF_ADD("[Request Info]\n");
+	wasi_http_types_method_incoming_request_path_with_query(b_req, &prstr);
+	BUF_ADD("REQUEST_PATH = %.*s\n", (int)prstr.len, prstr.ptr);
+	wasi_http_types_method_incoming_request_method(b_req, &method);
+	BUF_ADD("METHOD       = %s\n", http_method_map[method.tag].method);
+	ptr = memchr(prstr.ptr, '?', prstr.len);
+	BUF_ADD("QUERY        = %.*s\n",
+		ptr ? (int)(((char *)(prstr.ptr + prstr.len)) - ptr - 1) : 0,
+		ptr ? ptr + 1 : "");
+
+	BUF_ADD("\n[Request Headers]\n");
+	hdrs = wasi_http_types_method_incoming_request_headers(b_req);
+	b_hdrs = wasi_http_types_borrow_fields(hdrs);
+
+	wasi_http_types_method_fields_entries(b_hdrs, &fvk);
+	for (size_t i = 0; i < fvk.len; i++)
+		BUF_ADD("%.*s = %.*s\n",
+			(int)fvk.ptr[i].f0.len, fvk.ptr[i].f0.ptr,
+			(int)fvk.ptr[i].f1.len, fvk.ptr[i].f1.ptr);
+
+	wasi_http_types_list_tuple2_field_key_field_value_free(&fvk);
+
+	ok = wasi_http_types_method_incoming_request_consume(b_req, &r_body);
+	if (!ok)
+		ex("wasi_http_types_method_incoming_request_consume() failed\n");
+	b_r_body = wasi_http_types_borrow_incoming_body(r_body);
+	ok = wasi_http_types_method_incoming_body_stream(b_r_body, &in_stream);
+	if (!ok)
+		ex("wasi_http_types_method_incoming_body_stream() failed\n");
+	b_in_stream = wasi_io_streams_borrow_input_stream(in_stream);
+
+	ok = wasi_io_streams_method_input_stream_read(b_in_stream,
+						      8 * 1024*1024,
+						      &data,
+						      &in_stream_err);
+
+	if (method.tag == WASI_HTTP_TYPES_METHOD_POST ||
+	    method.tag == WASI_HTTP_TYPES_METHOD_PUT) {
+		BUF_ADD("\n[%s data]\n",
+			http_method_map[method.tag].method);
+		BUF_ADD("%.*s\n", (int)data.len, data.ptr);
+	}
+
+	fclose(out);
+
+	fields = wasi_http_types_constructor_fields();
+	b_fields = wasi_http_types_borrow_fields(fields);
+
+	proxy_string_set((proxy_string_t *)&key, "Content-Length");
+	sprintf(clen, "%zu", size);
+	proxy_string_set((proxy_string_t *)&value, clen);
+
+	ok = wasi_http_types_method_fields_append(b_fields, &key, &value,
+						  &hdr_err);
+	if (!ok)
+		ex("wasi_http_types_method_fields_append() failed\n");
+
+	resp = wasi_http_types_constructor_outgoing_response(fields);
+
+	b_resp = wasi_http_types_borrow_outgoing_response(resp);
+	ok = wasi_http_types_method_outgoing_response_body(b_resp, &body);
+	if (!ok)
+		ex("wasi_http_types_method_outgoing_response_body() failed\n");
+	b_body = wasi_http_types_borrow_outgoing_body(body);
+
+	ok = wasi_http_types_method_outgoing_body_write(b_body, &out_stream);
+	if (!ok)
+		ex("wasi_http_types_method_outgoing_body_write() failed\n");
+	b_out_stream = wasi_io_streams_borrow_output_stream(out_stream);
+
+	stream_data.len = size;
+	stream_data.ptr = (uint8_t *)out_ptr;
+	ok = wasi_io_streams_method_output_stream_write(b_out_stream,
+							&stream_data,
+							&stream_err);
+	if (!ok)
+		ex("wasi_io_streams_method_output_stream_write() failed\n");
+
+	free(out_ptr);
+
+	wasi_http_types_static_response_outparam_set(response_out, &rerr);
+
+	wasi_io_streams_output_stream_drop_borrow(out_stream);
+
+	ok = wasi_http_types_static_outgoing_body_finish(body, NULL, &http_err);
+	if (!ok)
+		ex("wasi_http_types_static_outgoing_body_finish() failed\n");
+}