From a456da66a46c203328420b9f89dce64ce5131fa3 Mon Sep 17 00:00:00 2001
From: mykola2312 <nikolay_tihonov@i.ua>
Date: Sun, 31 Mar 2024 17:41:07 +0300
Subject: [PATCH] begin working on proper stdout / stderr piping because we
 need it for yt-dlp file output and proper stderr parsing on the fly (for
 progress bars in future)

---
 src/dl/spawn.rs  | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/dl/yt_dlp.rs | 13 ++++++---
 2 files changed, 81 insertions(+), 4 deletions(-)

diff --git a/src/dl/spawn.rs b/src/dl/spawn.rs
index fa4b61c..c136f15 100644
--- a/src/dl/spawn.rs
+++ b/src/dl/spawn.rs
@@ -1,12 +1,18 @@
 use core::fmt;
 use std::process::Output;
 use std::str::Utf8Error;
+use std::{fs::OpenOptions, process::Stdio};
+use tokio::io::AsyncReadExt;
 use tokio::process::Command;
 use tracing::{event, Level};
 
+use super::tmpfile::TmpFile;
+
 #[derive(Debug)]
 pub enum SpawnError {
     CommandError(std::io::Error),
+    NoStdErr,
+    PipeError(std::io::Error),
     UtfError(Utf8Error),
     ErrorMessage(String),
 }
@@ -28,6 +34,8 @@ impl fmt::Display for SpawnError {
         use SpawnError as FE;
         match self {
             FE::CommandError(e) => write!(f, "Command::new - {}", e),
+            FE::NoStdErr => write!(f, "spawned process has closed stderr!"),
+            FE::PipeError(e) => write!(f, "pipe error - {}", e),
             FE::UtfError(_) => write!(f, "Error while decoding UTF8"),
             FE::ErrorMessage(msg) => write!(f, "ffmpeg error - {}", msg),
         }
@@ -51,3 +59,67 @@ pub async fn spawn(program: &str, args: &[&str]) -> Result<Output, SpawnError> {
 
     Ok(output)
 }
+
+pub async fn spawn_pipe(
+    program: &str,
+    args: &[&str],
+    output_file: &TmpFile,
+) -> Result<(), SpawnError> {
+    {
+        let cmd_args = args.join(" ");
+        event!(Level::INFO, "{} {}", program, cmd_args);
+    }
+
+    let output_file = OpenOptions::new()
+        .create(true)
+        .write(true)
+        .open(&output_file.path)
+        .map_err(|e| SpawnError::PipeError(e))?;
+
+    let mut process = Command::new(program)
+        .args(args)
+        .stdout(output_file)
+        .stderr(Stdio::piped())
+        .spawn()?;
+    let mut stderr = process.stderr.take().ok_or(SpawnError::NoStdErr)?;
+
+    let result = process.wait().await?;
+
+    if !result.success() {
+        let mut data: Vec<u8> = Vec::new();
+        stderr.read_to_end(&mut data).await?;
+
+        let message = std::str::from_utf8(&data)?;
+        return Err(SpawnError::ErrorMessage(message.to_string()));
+    }
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::dl::spawn::{spawn_pipe, SpawnError};
+    use crate::dl::tmpfile::TmpFile;
+
+    #[tokio::test]
+    async fn test_spawn_pipe() {
+        let stdout = TmpFile::new("stdout.test").unwrap();
+        let result = spawn_pipe(
+            "python",
+            &[
+                "-c",
+                "import sys; print(file=sys.stderr, 'stderr test'); sys.exit(1)",
+            ],
+            &stdout,
+        )
+        .await;
+
+        assert_eq!(true, result.is_err());
+        if let Err(e) = result {
+            match e {
+                SpawnError::ErrorMessage(msg) => assert_eq!("stderr test", msg),
+                _ => panic!("SpawnError is not ErrorMessage!")
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/dl/yt_dlp.rs b/src/dl/yt_dlp.rs
index ae8495a..f76d7b0 100644
--- a/src/dl/yt_dlp.rs
+++ b/src/dl/yt_dlp.rs
@@ -1,4 +1,4 @@
-use super::spawn::{spawn, SpawnError};
+use super::spawn::{spawn, spawn_pipe, SpawnError};
 use super::tmpfile::{TmpFile, TmpFileError};
 use core::fmt;
 use ordered_float::OrderedFloat;
@@ -254,21 +254,26 @@ impl YtDlp {
     }
 
     pub async fn download(url: &str, info: &YtDlpInfo) -> Result<TmpFile, YtDlpError> {
-        let file = TmpFile::new(&format!("{}.bin", info.id))?;
+        let file = TmpFile::new(&info.id)?;
 
-        spawn(
+        // since yt-dlp tend to randomly choose filename we can't rely on it,
+        // and instead output to stdout and then pipe to our file
+        // that way we can avoid bugs related to filename confusion
+        let output = spawn_pipe(
             "python",
             &[
                 "-m",
                 "yt_dlp",
                 url,
                 "-o",
-                &file.path,
+                "-",
                 "--force-overwrites",
                 "--no-exec",
             ],
+            &file,
         )
         .await?;
+        dbg!(output);
 
         match file.exists() {
             true => Ok(file),