Update client

This PR uses the `proxy` feature of rust-jsonrpc to create a http transport
via sock5 proxy. Which can be activated using the `proxy` feature of this library.
 - Update Cargo.toml to include `proxy` feature.
 - Add a new `new_with_proxy()` constructor for client.

client/Cargo.toml

@@ -22,8 +22,11 @@ path = "src/lib.rs"
 bitcoincore-rpc-json = { version = "0.16.0", path = "../json" }
 
 log = "0.4.5"
-jsonrpc = "0.13.0"
+jsonrpc = { git = "https://github.com/apoelstra/rust-jsonrpc", rev = "7c94adf8aad7d55afad8f890ab1fbc79ecb7abc7"}
 
 # Used for deserialization of JSON.
 serde = "1"
 serde_json = "1"
+
+[features]
+proxy = ["jsonrpc/proxy"]

client/src/client.rs

@@ -1217,6 +1217,22 @@ impl Client {
             .map_err(|e| super::error::Error::JsonRpc(e.into()))
     }
 
+    #[cfg(feature = "proxy")]
+    /// Creates a client to a bitcoind JSON-RPC server via SOCK5 proxy.
+    pub fn new_with_proxy(
+        url: &str,
+        auth: Auth,
+        proxy_addr: &str,
+        proxy_auth: Option<(&str, &str)>,
+    ) -> Result<Self> {
+        let (user, pass) = auth.get_user_pass()?;
+        jsonrpc::client::Client::http_proxy(url, user, pass, proxy_addr, proxy_auth)
+            .map(|client| Client {
+                client,
+            })
+            .map_err(|e| super::error::Error::JsonRpc(e.into()))
+    }
+
     /// Create a new Client using the given [jsonrpc::Client].
     pub fn from_jsonrpc(client: jsonrpc::client::Client) -> Client {
         Client {