w-h/0.2.0: Add a new example program env-var

This shows how to get access to the environment variables and echos
them back to the client.

We need to include wasi:cli/environment@0.2.0 in the proxy world.

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

2 files changed, 134 insertions, 0 deletions

diff --git a/c/wasi-http/0.2.0/env-var/Makefile b/c/wasi-http/0.2.0/env-var/Makefile
new file mode 100644
index 0000000..062aef4
--- /dev/null
+++ b/c/wasi-http/0.2.0/env-var/Makefile
@@ -0,0 +1,29 @@
+# Look for wasi-sysroot in some common places, falling back
+# to provided WASI_SYSROOT
+ifneq ("$(wildcard /usr/wasm32-wasi)", "")
+        # Fedora
+        WASI_SYSROOT ?= /usr/wasm32-wasi
+endif
+
+export WASI_SYSROOT
+
+CC      = clang
+CFLAGS  = -Wall -Wextra --target=wasm32-wasi --sysroot=$(WASI_SYSROOT)
+LDFLAGS = -Wl,--no-entry,--export=__heap_base,--export=__data_end,--export=malloc,--export=free,--stack-first,-z,stack-size=$$((8*1024*1024)) -mexec-model=reactor --rtlib=compiler-rt
+
+all: component.wasm
+
+bindgen:
+	/home/andrew/src/c/wasm/git/wit-bindgen/target/release/wit-bindgen c ../../wit/wasi-http/0.2.0 --autodrop-borrows yes --world proxy
+	/home/andrew/src/c/wasm/git/wit-bindgen/target/release/wit-bindgen markdown ../../wit/wasi-http/0.2.0 --world proxy
+
+.PHONY:
+module.wasm: bindgen
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ proxy.c proxy_component_type.o component.c
+
+.PHONY:
+component.wasm: module.wasm
+	/home/andrew/src/c/wasm/git/wasm-tools/target/release/wasm-tools component new module.wasm --adapt ../../adaptors/24.0.0/wasi_snapshot_preview1.reactor.wasm -o component.wasm
+
+clean:
+	rm -f component.wasm module.wasm proxy*
diff --git a/c/wasi-http/0.2.0/env-var/component.c b/c/wasi-http/0.2.0/env-var/component.c
new file mode 100644
index 0000000..1fff245
--- /dev/null
+++ b/c/wasi-http/0.2.0/env-var/component.c
@@ -0,0 +1,105 @@
+/* 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 "proxy.h"
+
+#define ex(...) \
+	do { \
+		printf(__VA_ARGS__); \
+		exit(EXIT_FAILURE); \
+	} while (0);
+
+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 clen[32];
+	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;
+	proxy_list_u8_t stream_data;
+	wasi_io_streams_stream_error_t stream_err;
+	wasi_http_types_header_error_t hdr_err;
+	wasi_http_types_field_key_t key;
+	wasi_http_types_field_value_t value;
+	proxy_list_tuple2_string_string_t env;
+
+	(void)request;
+
+	out = open_memstream(&out_ptr, &size);
+
+#define BUF_ADD(fmt, ...) \
+	fprintf(out, fmt, ##__VA_ARGS__);
+
+	BUF_ADD("*** Environment Variables ***\n\n");
+
+	wasi_cli_environment_get_environment(&env);
+	for (size_t i = 0; i < env.len; i++)
+		BUF_ADD("%.*s=%.*s\n",
+		       (int)env.ptr[i].f0.len, env.ptr[i].f0.ptr,
+		       (int)env.ptr[i].f1.len, env.ptr[i].f1.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-Type");
+	proxy_string_set((proxy_string_t *)&value, "text/plain");
+
+	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);
+	rerr.val.ok = resp;
+
+	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_blocking_write_and_flush() failed\n");
+
+	wasi_http_types_static_response_outparam_set(response_out, &rerr);
+
+	free(out_ptr);
+}