WIP: Fetching API data through WASM

Author: FranklinWaller

examples/simple-url-call/Cargo.lock

@@ -7,3 +7,6 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+jsonpath-rust = "0.1.0"

examples/simple-url-call/Cargo.toml

@@ -1,3 +1,8 @@
+use std::str;
+use serde::Deserialize;
+use serde_json::{ json, from_str };
+use std::collections::HashMap;
+
 mod raw;
 
 pub fn get_used_gas() -> i64 {
@@ -8,12 +13,73 @@ pub fn get_call_result_size() -> u32 {
     unsafe { raw::call_result_size() }
 }
 
-pub fn call() {
-    let call_data = "This is some call data";
+pub struct HttpCallOptions {
+    method: Option<String>,
+    body: Option<String>,
+    headers: Option<HashMap<String, String>>,
+}
+
+#[derive(Deserialize)]
+struct RawCallResult {
+    status: i32,
+    result: String,
+    error: bool,
+}
+
+#[derive(Debug)]
+pub struct CallResult {
+    pub status: i32,
+    pub result: String,
+}
+
+#[derive(Debug)]
+pub struct CallResultError {
+    pub error: String,
+    pub status: i32,
+}
+
+pub fn http_call(url: &str, options: Option<HttpCallOptions>) -> Result<CallResult, CallResultError> {
+    let unwrapped_options = options.unwrap_or(HttpCallOptions {
+        method: Some("GET".to_string()),
+        body: None,
+        headers: None,
+    });
+
+    let call_data = json!({
+        "url": url,
+        "type": "http",
+        "options": {
+            "headers": unwrapped_options.headers,
+            "body": unwrapped_options.body,
+            "method": unwrapped_options.method.unwrap_or("GET".to_string()),
+        }
+    }).to_string();
 
     unsafe {
-        raw::call(call_data.as_ptr(), call_data.len() as i32);
+        raw::http_call(call_data.as_ptr(), call_data.len() as i32);
     }
 
-    let mut result_data: Vec<u8> = Vec::with_capacity(get_call_result_size() as usize);
-}
+    let mut result_data: Vec<u8> = Vec::new();
+    result_data.resize(get_call_result_size() as usize, 0);
+
+    unsafe {
+        raw::call_result_copy(result_data.as_ptr())
+    }
+
+    let result = str::from_utf8(&result_data);
+    let unwrapped_result = result.unwrap_or("ERR_PARSING_RESULT");
+
+    let parsed_result: RawCallResult = from_str(unwrapped_result).unwrap();
+
+    if parsed_result.error {
+        return Err(CallResultError {
+            error: parsed_result.result,
+            status: parsed_result.status,
+        });
+    }
+
+    return Ok(CallResult {
+        status: parsed_result.status,
+        result: parsed_result.result,
+    });
+}

examples/simple-url-call/src/flux/mod.rs

@@ -1,6 +1,6 @@
 extern "C" {
-    pub fn call(call_data_offset: *const u8, call_data_length: i32);
+    pub fn http_call(call_data_offset: *const u8, call_data_length: i32);
     pub fn call_result_size() -> u32;
-    pub fn call_result_copy(result_offset: i32);
+    pub fn call_result_copy(result_offset: *const u8);
     pub fn gas_used() -> i64;
 }