low level js bindings

client/build.sh

@@ -5,9 +5,10 @@ LIB_DIR="build/curl-wasm/lib/"
 CACERT_FILE="cacert.pem"
 OUT_FILE="out/libcurl.js"
 
-EXPORTED_FUNCS="_main,_do_request"
+EXPORTED_FUNCS="_main,_perform_request,_copy_bytes"
+RUNTIME_METHODS="addFunction,removeFunction"
 COMPILER_OPTIONS="-o $OUT_FILE -lcurl -lssl -lcrypto -I $INCLUDE_DIR -L $LIB_DIR"
-EMSCRIPTEN_OPTIONS="-lwebsocket.js -sWEBSOCKET_URL=wss://debug.ading.dev/ws -sASYNCIFY -sALLOW_UNIMPLEMENTED_SYSCALLS -sEXPORTED_FUNCTIONS=$EXPORTED_FUNCS --preload-file $CACERT_FILE"
+EMSCRIPTEN_OPTIONS="-lwebsocket.js -sWEBSOCKET_URL=wss://debug.ading.dev/ws -sASYNCIFY -sALLOW_TABLE_GROWTH -sEXPORTED_FUNCTIONS=$EXPORTED_FUNCS -sEXPORTED_RUNTIME_METHODS=$RUNTIME_METHODS --preload-file $CACERT_FILE"
 
 if [ ! -f $CACERT_FILE ]; then
   wget "https://curl.se/ca/cacert.pem" -O $CACERT_FILE

client/main.c

@@ -1,9 +1,19 @@
-#include "emscripten/emscripten.h"
+#include <stdlib.h>
 #include <stdio.h>
 #include <curl/curl.h>
 #include <emscripten.h>
+#include <string.h>
+
+int write_function(void *data, size_t size, size_t nmemb, void(*data_callback)(char* chunk_ptr, int chunk_size)) {
+  long real_size = size * nmemb;
+  char* chunk = malloc(real_size);
+  memcpy(chunk, data, real_size);
+  data_callback(chunk, real_size);
+  free(chunk);
+  return real_size;
+}
  
-int do_request(const char* url) {
+void perform_request(const char* url, void(*data_callback)(char* chunk_ptr, int chunk_size), void(*end_callback)()) {
   printf("downloading %s\n", url);
 
   CURL *http_handle;
@@ -18,6 +28,11 @@ int do_request(const char* url) {
   curl_easy_setopt(http_handle, CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5);
   curl_easy_setopt(http_handle, CURLOPT_CAINFO, "/cacert.pem");
   curl_easy_setopt(http_handle, CURLOPT_CAPATH, "/cacert.pem");
+
+  //callbacks to pass the response data back to js
+  curl_easy_setopt(http_handle, CURLOPT_WRITEFUNCTION, &write_function);
+  curl_easy_setopt(http_handle, CURLOPT_WRITEDATA, data_callback);
+  
  
   multi_handle = curl_multi_init();
   curl_multi_add_handle(multi_handle, http_handle);
@@ -42,11 +57,16 @@ int do_request(const char* url) {
   curl_easy_cleanup(http_handle);
   curl_multi_cleanup(multi_handle);
   curl_global_cleanup();
- 
-  return 0;
+
+  (*end_callback)();
+}
+
+char* copy_bytes(const char* ptr, const int size) {
+  char* new_ptr = malloc(size);
+  memcpy(new_ptr, ptr, size);
+  return new_ptr;
 }
 
 int main() {
   printf("emscripten libcurl module loaded\n");
-  do_request("https://ifconfig.me/all");
 }

client/main.js

@@ -5,8 +5,55 @@ function allocate_str(str) {
   return allocate(intArrayFromString(str), ALLOC_NORMAL);
 }
 
-async function main() {
+//low level interface with c code
+function perform_request(url, js_data_callback, js_end_callback) {
+  let end_callback_ptr;
+  let data_callback_ptr;
+  let url_ptr = allocate_str(url);
 
+  let end_callback = () => {
+    Module.removeFunction(end_callback_ptr);
+    Module.removeFunction(data_callback_ptr);
+    _free(url_ptr);
+    
+    js_end_callback();
+  }
+
+  let data_callback = (chunk_ptr, chunk_size) => {
+    let data = Module.HEAPU8.subarray(chunk_ptr, chunk_ptr + chunk_size);
+    let chunk = new Uint8Array(data);
+    js_data_callback(chunk);
+  }
+
+  end_callback_ptr = Module.addFunction(end_callback, "v");
+  data_callback_ptr = Module.addFunction(data_callback, "vii");
+  _perform_request(url_ptr, data_callback_ptr, end_callback_ptr);
+}
+
+function merge_arrays(arrays) {
+  let total_len = arrays.reduce((acc, val) => acc + val.length, 0);
+  let new_array = new Uint8Array(total_len);
+  let offset = 0;
+  for (let array of arrays) {
+    new_array.set(array, offset);
+    offset += array.length;
+  }
+  return new_array;
+}
+
+async function main() {
+  let chunks = [];
+  perform_request("https://ading.dev", (new_data) => {
+    chunks.push(new_data);
+  }, () => {
+    for (let chunk of chunks) {
+      console.log(chunk);
+    }
+
+    let response_data = merge_arrays(chunks);
+    let response_str = new TextDecoder().decode(response_data);
+    console.log(response_str);
+  });
 }
 
 window.onload = () => {