Implement Deref<Target=UrlClient> for EsploraBlockchain

There is currently no way to access the client
from the EsploraBlockchain. This makes it difficult
for users to extend it's functionality. This PR exposes
both the reqwest and ureq clients. This PR is related to
PR bitcoindevkit#705.

Author: vladimirfomene

src/blockchain/esplora/reqwest.rs

@@ -32,7 +32,7 @@ use crate::error::Error;
 use crate::FeeRate;
 
 #[derive(Debug)]
-struct UrlClient {
+pub struct UrlClient {
     url: String,
     // We use the async client instead of the blocking one because it automatically uses `fetch`
     // when the target platform is wasm32.
@@ -46,6 +46,7 @@ struct UrlClient {
 /// See the [`blockchain::esplora`](crate::blockchain::esplora) module for a usage example.
 #[derive(Debug)]
 pub struct EsploraBlockchain {
+    /// Esplora reqwest client
     url_client: UrlClient,
     stop_gap: usize,
 }
@@ -101,6 +102,14 @@ impl Blockchain for EsploraBlockchain {
     }
 }
 
+impl Deref for EsploraBlockchain {
+    type Target = UrlClient;
+
+    fn deref(&self) -> &Self::Target {
+        &self.url_client
+    }
+}
+
 impl StatelessBlockchain for EsploraBlockchain {}
 
 #[maybe_async]

src/blockchain/esplora/ureq.rs

@@ -34,7 +34,7 @@ use crate::error::Error;
 use crate::FeeRate;
 
 #[derive(Debug, Clone)]
-struct UrlClient {
+pub struct UrlClient {
     url: String,
     agent: Agent,
 }
@@ -45,6 +45,7 @@ struct UrlClient {
 /// See the [`blockchain::esplora`](crate::blockchain::esplora) module for a usage example.
 #[derive(Debug)]
 pub struct EsploraBlockchain {
+    /// Esplora ureq client
     url_client: UrlClient,
     stop_gap: usize,
     concurrency: u8,
@@ -98,6 +99,14 @@ impl Blockchain for EsploraBlockchain {
     }
 }
 
+impl Deref for EsploraBlockchain {
+    type Target = UrlClient;
+
+    fn deref(&self) -> &Self::Target {
+        &self.url_client
+    }
+}
+
 impl StatelessBlockchain for EsploraBlockchain {}
 
 impl GetHeight for EsploraBlockchain {