feat(cast): add tx command

This commit ports the `seth tx` command to `cast`.
It follows the implementation of `cast block` and includes
the feature to print a specific field in the transaction
as well as printing the result in JSON.

```
$ cast tx --rpc-url <url> <tx-hash> [field]
```

The flag `-j`/`--json` is used to print the result
as JSON.

Author: tynes

cast/README.md

@@ -35,7 +35,7 @@
 - [x] `calldata`
 - [x] `chain`
 - [x] `chain-id`
-- [ ] `code`
+- [x] `code`
 - [ ] `debug`
 - [ ] `estimate`
 - [ ] `etherscan-source`
@@ -56,4 +56,4 @@
 - [x] `send` (partial)
 - [ ] `sign`
 - [x] `storage`
-- [ ] `tx`
+- [x] `tx`

cast/src/lib.rs

@@ -44,7 +44,7 @@ where
     /// Makes a read-only call to the specified address
     ///
     /// ```no_run
-    /// 
+    ///
     /// use cast::Cast;
     /// use ethers_core::types::Address;
     /// use ethers_providers::{Provider, Http};
@@ -308,6 +308,45 @@ where
     ) -> Result<String> {
         Ok(format!("{}", self.provider.get_code(who, block).await?))
     }
+
+    /// ```no_run
+    /// use cast::Cast;
+    /// use ethers_providers::{Provider, Http};
+    /// use std::convert::TryFrom;
+    ///
+    /// # async fn foo() -> eyre::Result<()> {
+    /// let provider = Provider::<Http>::try_from("http://localhost:8545")?;
+    /// let cast = Cast::new(provider);
+    /// let tx_hash = "0xf8d1713ea15a81482958fb7ddf884baee8d3bcc478c5f2f604e008dc788ee4fc";
+    /// let tx = cast.transaction(tx_hash.to_string(), None, false).await?;
+    /// println!("{}", tx);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub async fn transaction(
+        &self,
+        tx_hash: String,
+        field: Option<String>,
+        to_json: bool,
+    ) -> Result<String> {
+        let transaction_result = self
+            .provider
+            .get_transaction(H256::from_str(&tx_hash)?)
+            .await?
+            .ok_or_else(|| eyre::eyre!("transaction {:?} not found", tx_hash))?;
+
+        let transaction = if let Some(ref field) = field {
+            serde_json::to_value(&transaction_result)?
+                .get(field)
+                .cloned()
+                .ok_or_else(|| eyre::eyre!("field {} not found", field))?
+        } else {
+            serde_json::to_value(&transaction_result)?
+        };
+
+        let transaction = if to_json { serde_json::to_string(&transaction)? } else { to_table(transaction) };
+        Ok(transaction)
+    }
 }
 
 pub struct SimpleCast;

cli/src/cast.rs

@@ -124,6 +124,10 @@ async fn main() -> eyre::Result<()> {
         Subcommands::Namehash { name } => {
             println!("{}", SimpleCast::namehash(&name)?);
         }
+        Subcommands::Tx { rpc_url, hash, field, to_json } => {
+            let provider = Provider::try_from(rpc_url)?;
+            println!("{}", Cast::new(&provider).transaction(hash, field, to_json).await?)
+        }
         Subcommands::SendTx { eth, to, sig, cast_async, args } => {
             let provider = Provider::try_from(eth.rpc_url.as_str())?;
             let chain_id = Cast::new(&provider).chain_id().await?;

cli/src/opts/cast.rs

@@ -107,6 +107,16 @@ pub enum Subcommands {
     #[structopt(name = "namehash")]
     #[structopt(about = "returns ENS namehash of provided name")]
     Namehash { name: String },
+    #[structopt(name = "tx")]
+    #[structopt(about = "Show information about the transaction <tx-hash>")]
+    Tx {
+        hash: String,
+        field: Option<String>,
+        #[structopt(long = "--json", short = "-j")]
+        to_json: bool,
+        #[structopt(long, env = "ETH_RPC_URL")]
+        rpc_url: String
+    },
     #[structopt(name = "send")]
     #[structopt(about = "Publish a transaction signed by <from> to call <to> with <data>")]
     SendTx {