feat(libs): add blockscout-chains crate (#1077)

* feat: add blockscout-chains crate

* feat: add derives

* fix: change chain_id type

* feat: add builder

* chore: remove unused deps

libs/Cargo.toml

@@ -2,6 +2,7 @@
 resolver = "2"
 members = [
     "blockscout-auth",
+    "blockscout-chains",
     "blockscout-client/crate",
     "blockscout-db",
     "endpoints/swagger",

libs/blockscout-chains/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "blockscout-chains"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"] }
+reqwest = { version = "0.12", features = ["json"] }
+reqwest-middleware = "0.3"
+reqwest-retry = "0.6"
+
+[dev-dependencies]
+tokio = { version = "1.0", features = ["macros"] }

libs/blockscout-chains/src/lib.rs

@@ -0,0 +1,112 @@
+use reqwest_middleware::{ClientBuilder, ClientWithMiddleware};
+use reqwest_retry::{policies::ExponentialBackoff, RetryTransientMiddleware};
+use serde::Deserialize;
+use std::collections::HashMap;
+
+const CHAINS_URL: &str = "https://chains.blockscout.com/api/chains";
+
+pub struct BlockscoutChainsClient {
+    client: ClientWithMiddleware,
+    url: String,
+}
+
+impl BlockscoutChainsClient {
+    pub fn builder() -> BlockscoutChainsClientBuilder {
+        Default::default()
+    }
+
+    pub async fn fetch_all(&self) -> Result<BlockscoutChains, reqwest_middleware::Error> {
+        let res = self.client.get(&self.url).send().await?;
+        let chains: BlockscoutChains = res.json().await?;
+        Ok(chains)
+    }
+}
+
+impl Default for BlockscoutChainsClient {
+    fn default() -> Self {
+        Self::builder().build()
+    }
+}
+
+pub struct BlockscoutChainsClientBuilder {
+    max_retries: u32,
+    url: String,
+}
+
+impl BlockscoutChainsClientBuilder {
+    pub fn with_max_retries(mut self, max_retries: u32) -> Self {
+        self.max_retries = max_retries;
+        self
+    }
+
+    pub fn with_url(mut self, url: String) -> Self {
+        self.url = url;
+        self
+    }
+
+    pub fn build(self) -> BlockscoutChainsClient {
+        let retry_policy = ExponentialBackoff::builder().build_with_max_retries(self.max_retries);
+        let client = ClientBuilder::new(reqwest::Client::new())
+            .with(RetryTransientMiddleware::new_with_policy(retry_policy))
+            .build();
+        BlockscoutChainsClient {
+            client,
+            url: self.url,
+        }
+    }
+}
+
+impl Default for BlockscoutChainsClientBuilder {
+    fn default() -> Self {
+        Self {
+            url: CHAINS_URL.to_string(),
+            max_retries: 3,
+        }
+    }
+}
+
+pub type BlockscoutChains = HashMap<u64, BlockscoutChainData>;
+
+#[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct BlockscoutChainData {
+    pub name: String,
+    pub description: String,
+    pub ecosystem: Ecosystem,
+    pub is_testnet: Option<bool>,
+    pub layer: Option<u8>,
+    pub rollup_type: Option<String>,
+    pub website: String,
+    pub explorers: Vec<ExplorerConfig>,
+    pub logo: String,
+}
+
+#[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
+#[serde(untagged)]
+pub enum Ecosystem {
+    Single(String),
+    Multiple(Vec<String>),
+}
+
+#[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
+#[serde(rename_all = "camelCase")]
+pub struct ExplorerConfig {
+    pub url: String,
+    pub hosted_by: String,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn test_get_blockscout_chains() {
+        let chains = BlockscoutChainsClient::builder()
+            .with_max_retries(0)
+            .build()
+            .fetch_all()
+            .await
+            .unwrap();
+        assert!(!chains.is_empty());
+    }
+}