feat: make reqwest optional but enabled by default (#580)

* feat: make reqwest optional but enabled by default

* update changelog

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Unreleased
 
+- Provide a way to opt out of networking support in abigen proc macro with `abigen-offline` feature [#580](https://github.com/gakonst/ethers-rs/pull/580)
 - Add `.call()` method to `Deployer` for performing dry runs of contract deployments. [#554](https://github.com/gakonst/ethers-rs/pull/554)
 - Improve error message from failure in `ethers_contract_abigen::Source::parse` [#552](https://github.com/gakonst/ethers-rs/pull/552)
 - use enumerated aliases for overloaded functions [#545](https://github.com/gakonst/ethers-rs/pull/545)

Cargo.toml

@@ -72,6 +72,8 @@ ledger = ["ethers-signers/ledger"]
 yubi = ["ethers-signers/yubi"]
 ## contracts
 abigen = ["ethers-contract/abigen"]
+### abigen without reqwest
+abigen-offline = ["ethers-contract/abigen-offline"]
 ## solc
 solc-async = ["ethers-solc/async"]
 solc-full = ["ethers-solc/full"]

ethers-contract/Cargo.toml

@@ -12,7 +12,7 @@ keywords = ["ethereum", "web3", "celo", "ethers"]
 [dependencies]
 ethers-providers = { version = "^0.5.0", path = "../ethers-providers", default-features = false }
 ethers-core = { version = "^0.5.0", path = "../ethers-core", default-features = false }
-ethers-contract-abigen = { version = "^0.5.0", path = "ethers-contract-abigen", optional = true }
+ethers-contract-abigen = { version = "^0.5.0", path = "ethers-contract-abigen",  default-features = false, optional = true }
 ethers-contract-derive = { version = "^0.5.0", path = "ethers-contract-derive", optional = true }
 ethers-derive-eip712 = { version = "0.1.0", path = "../ethers-core/ethers-derive-eip712", optional = true }
 
@@ -39,7 +39,8 @@ tokio = { version = "1.5", default-features = false, features = ["macros"] }
 
 [features]
 eip712 = ["ethers-derive-eip712", "ethers-core/eip712"]
-abigen = ["ethers-contract-abigen", "ethers-contract-derive"]
+abigen = ["ethers-contract-abigen/reqwest", "ethers-contract-derive"]
+abigen-offline = ["ethers-contract-abigen", "ethers-contract-derive"]
 celo = ["legacy", "ethers-core/celo", "ethers-core/celo", "ethers-providers/celo"]
 legacy = []
 

ethers-contract/ethers-contract-abigen/Cargo.toml

@@ -21,14 +21,17 @@ url = "2.1"
 serde_json = "1.0.61"
 serde = { version = "1.0.124", features = ["derive"] }
 hex = { version = "0.4.2", default-features = false, features = ["std"] }
-reqwest = { version = "0.11.3", features = ["blocking"] }
+reqwest = { version = "0.11.3", features = ["blocking"] , optional = true }
 once_cell = "1.8.0"
 cfg-if = "1.0.0"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 # NOTE: this enables wasm compatibility for getrandom indirectly
 getrandom = { version = "0.2", features = ["js"] }
 
+[features]
+default = ["reqwest"]
+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]

ethers-contract/ethers-contract-abigen/src/util.rs

@@ -1,6 +1,7 @@
 use ethers_core::types::Address;
 
 use anyhow::{anyhow, Result};
+use cfg_if::cfg_if;
 use inflector::Inflector;
 use proc_macro2::{Ident, Literal, Span, TokenStream};
 use quote::quote;
@@ -69,10 +70,15 @@ where
     Ok(address_str[2..].parse()?)
 }
 
-#[cfg(not(target_arch = "wasm32"))]
 /// Perform an HTTP GET request and return the contents of the response.
-pub fn http_get(url: &str) -> Result<String> {
-    Ok(reqwest::blocking::get(url)?.text()?)
+pub fn http_get(_url: &str) -> Result<String> {
+    cfg_if! {
+        if #[cfg(any(not(target_arch = "wasm32"), not(features = "reqwest")))]{
+            Err(anyhow!("HTTP is unsupported"))
+        } else {
+            Ok(reqwest::blocking::get(_url)?.text()?)
+        }
+    }
 }
 
 #[cfg(test)]