From b176d4df62390de2c51a139fdc4ae5727c20d08e Mon Sep 17 00:00:00 2001
From: Paul Oliver <puzza007@gmail.com>
Date: Mon, 9 Aug 2021 11:39:42 +1200
Subject: [PATCH] WIP json using reqwest/serde

---
 native/Cargo.lock      | 31 +++++++++++++++++++++++++++++++
 native/Cargo.toml      |  5 +++++
 native/src/lib.rs      | 11 ++++++++++-
 src/erqwest.erl        |  2 ++
 test/erqwest_SUITE.erl | 10 ++++++++++
 5 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/native/Cargo.lock b/native/Cargo.lock
index 3a944b1..d4bdb8a 100644
--- a/native/Cargo.lock
+++ b/native/Cargo.lock
@@ -118,11 +118,16 @@ dependencies = [
 name = "erqwest"
 version = "0.1.0"
 dependencies = [
+ "bytes",
  "futures",
  "lazy_static",
  "reqwest",
  "rustler",
  "rustler_codegen",
+ "serde",
+ "serde-transcode",
+ "serde_json",
+ "serde_rustler",
  "tokio",
 ]
 
@@ -616,6 +621,12 @@ dependencies = [
  "url",
 ]
 
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+
 [[package]]
 name = "quote"
 version = "1.0.9"
@@ -824,6 +835,15 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-transcode"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "590c0e25c2a5bb6e85bf5c1bce768ceb86b316e7a01bdf07d2cb4ec2271990e2"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_derive"
 version = "1.0.126"
@@ -846,6 +866,17 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_rustler"
+version = "0.1.0"
+source = "git+https://github.com/satoren/serde_rustler?branch=rustler_0.22#0273c8aff4d9407f046dd9bf5d5f61d309d9a55f"
+dependencies = [
+ "lazy_static",
+ "quick-error",
+ "rustler",
+ "serde",
+]
+
 [[package]]
 name = "serde_urlencoded"
 version = "0.7.0"
diff --git a/native/Cargo.toml b/native/Cargo.toml
index 7f3ff96..015b18d 100644
--- a/native/Cargo.toml
+++ b/native/Cargo.toml
@@ -11,6 +11,11 @@ crate-type = ["cdylib"]
 [dependencies]
 rustler = "0.22.0"
 rustler_codegen = "0.22.0"
+bytes = "1.0.1"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+serde_rustler = { git = "https://github.com/satoren/serde_rustler", branch = "rustler_0.22" }
+serde-transcode = "1.1"
 lazy_static = "1.0.0"
 reqwest = { version = "0.11", features = ["native-tls", "cookies"] }
 tokio = { version = "1", features = ["rt-multi-thread", "sync"] }
diff --git a/native/src/lib.rs b/native/src/lib.rs
index 428d6c2..c3df9c6 100644
--- a/native/src/lib.rs
+++ b/native/src/lib.rs
@@ -9,6 +9,7 @@ use std::sync::RwLock;
 use std::thread;
 use std::time::Duration;
 use tokio::runtime::{Handle, Runtime};
+use bytes::BufMut;
 
 mod atoms {
     rustler::atoms! {
@@ -26,6 +27,7 @@ mod atoms {
         headers,
         https_only,
         identity,
+        json,
         method,
         ok,
         pool_idle_timeout,
@@ -333,7 +335,14 @@ fn req_async_internal(
     };
     if let Ok(term) = req.map_get(atoms::body().encode(env)) {
         req_builder = req_builder.body(term.decode::<Binary>()?.as_slice().to_owned());
-    };
+    } else if let Ok(term) = req.map_get(atoms::json().encode(env)) {
+        let mut buf = vec![].writer();
+        serde_transcode::transcode(
+            serde_rustler::Deserializer::from(term),
+            &mut serde_json::Serializer::new(&mut buf)
+        ).or(Err(rustler::Error::RaiseAtom("json_encode_error")))?;
+        req_builder = req_builder.body(buf.into_inner());
+    }
     if let Ok(term) = req.map_get(atoms::timeout().encode(env)) {
         if let Some(timeout) = maybe_timeout(term.decode()?) {
             req_builder = req_builder.timeout(timeout);
diff --git a/src/erqwest.erl b/src/erqwest.erl
index 7c52823..aaf52a6 100644
--- a/src/erqwest.erl
+++ b/src/erqwest.erl
@@ -45,10 +45,12 @@
                 , method := method()
                 , headers => [header()]
                 , body => binary()
+                , json => term()
                 , timeout => timeout_ms()
                 }.
 -type req_opts() :: #{ headers => [header()]
                      , body => binary()
+                     , json => term()
                      , timeout => timeout_ms()
                      }.
 -type resp() :: #{ status := 100..599
diff --git a/test/erqwest_SUITE.erl b/test/erqwest_SUITE.erl
index ae22a77..5714873 100644
--- a/test/erqwest_SUITE.erl
+++ b/test/erqwest_SUITE.erl
@@ -76,6 +76,7 @@ groups() ->
      , get_http
      , https_only
      , post
+     , json
      , timeout
      , timeout_default
      , timeout_infinity
@@ -143,6 +144,15 @@ post(_Config) ->
                   , body => <<"!@#$%^&*()">>}),
   #{<<"data">> := <<"!@#$%^&*()">>} = jsx:decode(Body).
 
+json(_Config) ->
+  Json = #{<<"data">> => <<"!@#$%^&*()">>},
+  {ok, #{status := 200, body := Body, headers := Headers}} =
+  erqwest:post(default, <<"https://httpbin.org/post">>,
+                 #{json => Json}),
+  #{<<"data">> := JsonData} = jsx:decode(Body),
+  {<<"content-type">>, <<"application/json">>} = proplists:lookup(<<"content-type">>, Headers),
+  Json = jsx:decode(JsonData).
+
 timeout(_Config) ->
   {error, #{code := timeout}} =
     erqwest:get(default, <<"https://httpbin.org/delay/1">>, #{timeout => 500}).