From 6bcc81d4fc2c3f4e8330398859bee75166387bab Mon Sep 17 00:00:00 2001
From: A Farzat <a@farzat.xyz>
Date: Tue, 10 Mar 2026 12:28:21 +0300
Subject: Stream downloads to files directly

---
 src/epub.rs | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

(limited to 'src/epub.rs')

diff --git a/src/epub.rs b/src/epub.rs
index 9a59a7c..735bb1d 100644
--- a/src/epub.rs
+++ b/src/epub.rs
@@ -3,18 +3,17 @@ use crate::{
     xml::{build_epub_chapter, write_modified_opf},
 };
 use anyhow::{Context, Result};
+use futures_util::TryStreamExt;
 use ogrim::xml;
 use relative_path::{RelativePath, RelativePathBuf};
 use reqwest::Client;
 use std::{
     collections::HashMap,
-    io::{BufReader, Write, copy},
+    io::{BufReader, Write},
     path::Path,
 };
-use tokio::{
-    fs::{self, File},
-    io::AsyncWriteExt,
-};
+use tokio::fs::{self, File};
+use tokio_util::io::StreamReader;
 use zip::{CompressionMethod, ZipWriter, write::FileOptions};
 
 /// Creates and writes container.xml.
@@ -34,6 +33,7 @@ fn write_container_xml<W: Write>(out: &mut W, opf_full_path: &RelativePathBuf) -
     Ok(())
 }
 
+/// Downloads files to the relative location specified in full_path.
 pub async fn download_all_files(
     client: &Client,
     file_entries: &[FileEntry],
@@ -47,15 +47,15 @@ pub async fn download_all_files(
         }
 
         let mut file = File::create(dest_path).await?;
-        let bytes = client
+        let bytes_stream = client
             .get(entry.url.clone())
             .send()
             .await?
             .error_for_status()?
-            .bytes()
-            .await?;
+            .bytes_stream();
+        let mut reader = StreamReader::new(bytes_stream.map_err(std::io::Error::other));
 
-        file.write_all(&bytes).await?;
+        tokio::io::copy(&mut reader, &mut file).await?;
     }
     Ok(())
 }
@@ -122,7 +122,7 @@ pub fn create_epub_archive(
         } else if entry.ourn == opf_entry.ourn {
             write_modified_opf(buf_reader, &mut zip, &epub_data.descriptions.plain)?;
         } else {
-            copy(&mut buf_reader, &mut zip)?;
+            std::io::copy(&mut buf_reader, &mut zip)?;
         }
     }
 
-- 
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