?eval and ?play commands

Author: tinaun

src/main.rs

@@ -12,6 +12,7 @@ mod ban;
 mod commands;
 mod crates;
 mod db;
+mod playground;
 mod schema;
 mod state_machine;
 mod tags;
@@ -30,6 +31,7 @@ use std::collections::HashMap;
 struct Config {
     tags: bool,
     crates: bool,
+    eval: bool,
     discord_token: String,
     mod_id: String,
     talk_id: String,
@@ -108,6 +110,16 @@ fn app() -> Result<()> {
         cmds.help("?docs", "Lookup documentation", crates::doc_help);
     }
 
+    if config.eval {
+        // rust playground
+        cmds.add("?play ```\ncode```", playground::run);
+        cmds.add("?play code...", playground::help);
+
+        cmds.add("?eval `code`", playground::eval);
+        cmds.add("?eval ```\ncode```", playground::eval);
+        cmds.add("?eval code...", playground::eval_help);
+    }
+
     // Slow mode.
     // 0 seconds disables slowmode
     cmds.add_protected("?slowmode {channel} {seconds}", api::slow_mode, api::is_mod);

src/playground.rs

@@ -0,0 +1,172 @@
+//! run rust code on the rust-lang playground
+
+use crate::{
+    api,
+    commands::{Args, Result},
+};
+
+use reqwest::header;
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+#[derive(Debug, Serialize)]
+struct PlaygroundCode {
+    channel: Channel,
+    edition: Edition,
+    code: String,
+    #[serde(rename = "crateType")]
+    crate_type: CrateType,
+    mode: Mode,
+    tests: bool,
+}
+
+impl PlaygroundCode {
+    fn new(code: String) -> Self {
+        PlaygroundCode {
+            channel: Channel::Nightly,
+            edition: Edition::E2018,
+            code,
+            crate_type: CrateType::Binary,
+            mode: Mode::Debug,
+            tests: false,
+        }
+    }
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "snake_case")]
+enum Channel {
+    Stable,
+    Beta,
+    Nightly,
+}
+
+#[derive(Debug, Serialize)]
+enum Edition {
+    #[serde(rename = "2015")]
+    E2015,
+    #[serde(rename = "2018")]
+    E2018,
+}
+
+#[derive(Debug, Serialize)]
+enum CrateType {
+    #[serde(rename = "bin")]
+    Binary,
+    #[serde(rename = "lib")]
+    Library,
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "snake_case")]
+enum Mode {
+    Debug,
+    Release,
+}
+
+#[derive(Debug, Deserialize)]
+struct PlayResult {
+    success: bool,
+    stdout: String,
+    stderr: String,
+}
+
+fn run_code(args: &Args, code: &str) -> Result<String> {
+    info!("sending request to playground.");
+    let request = PlaygroundCode::new(code.to_string());
+
+    let resp = args
+        .http
+        .post("https://play.rust-lang.org/execute")
+        .json(&request)
+        .send()?;
+
+    let result: PlayResult = resp.json()?;
+
+    let result = if result.success {
+        result.stdout
+    } else {
+        result.stderr
+    };
+
+    Ok(if result.len() > 1994 {
+        format!(
+            "Output too large. Playground link: {}",
+            get_playground_link(args, code)?
+        )
+    } else {
+        format!("```{}```", result)
+    })
+}
+
+fn get_playground_link(args: &Args, code: &str) -> Result<String> {
+    let mut payload = HashMap::new();
+    payload.insert("code", code);
+
+    let resp = args
+        .http
+        .get("https://play.rust-lang.org/meta/gist/")
+        .header(header::REFERER, "https://discord.gg/rust-lang")
+        .json(&payload)
+        .send()?;
+
+    let resp = resp.text()?;
+    debug!("{:?}", resp);
+
+    Ok(resp)
+}
+
+pub fn run(args: Args) -> Result<()> {
+    let code = args
+        .params
+        .get("code")
+        .ok_or("Unable to retrieve param: query")?;
+
+    let result = run_code(&args, code)?;
+    api::send_reply(&args, &result)?;
+    Ok(())
+}
+
+pub fn help(args: Args) -> Result<()> {
+    let message = "Missing code block. Please use the following markdown:
+\\`\\`\\`rust
+    code here
+\\`\\`\\`
+    ";
+
+    api::send_reply(&args, message)?;
+    Ok(())
+}
+
+pub fn eval(args: Args) -> Result<()> {
+    let code = args
+        .params
+        .get("code")
+        .ok_or("Unable to retrieve param: query")?;
+
+    let code = format!(
+        "fn main(){{
+    println!(\"{{:?}}\",{{ 
+    {} 
+    }});
+}}",
+        code
+    );
+
+    let result = run_code(&args, &code)?;
+    api::send_reply(&args, &result)?;
+    Ok(())
+}
+
+pub fn eval_help(args: Args) -> Result<()> {
+    let message = "Missing code block. Please use the following markdown:
+    \\`code here\\`
+    or
+    \\`\\`\\`rust
+        code here
+    \\`\\`\\`
+    ";
+
+    api::send_reply(&args, message)?;
+    Ok(())
+}