refactor: separate the create_image function

src/main.rs

@@ -3,15 +3,20 @@ use async_zip::base::read::seek::ZipFileReader;
 use async_zip::base::write::ZipFileWriter;
 use async_zip::{Compression, ZipEntryBuilder};
 use infer;
-use magick_rust;
+use magick_rust::{self, MagickError};
 use std::env;
 use std::ffi::OsStr;
 use std::path::Path;
-use tokio::{
-    fs::File,
-    io::BufReader,
-};
-use tokio_util::compat::{TokioAsyncReadCompatExt };
+use tokio::{fs::File, io::BufReader};
+use tokio_util::compat::TokioAsyncReadCompatExt;
+
+fn compress_image(input: Vec<u8>, extension: &str) -> Result<Vec<u8>, MagickError> {
+    let wand = magick_rust::MagickWand::new();
+    wand.read_image_blob(input)?;
+    wand.fit(1200, 1600);
+    wand.strip_image()?;
+    wand.write_image_blob(extension)
+}
 
 #[tokio::main]
 async fn main() -> std::io::Result<()> {
@@ -52,12 +57,8 @@ async fn main() -> std::io::Result<()> {
                 .extension()
                 .and_then(OsStr::to_str)
                 .expect("String");
+            let to_write = compress_image(buf, extension).expect("Failed to compress image");
             println!("{}", extension);
-            let wand = magick_rust::MagickWand::new();
-            wand.read_image_blob(buf).expect("Successful read");
-            wand.fit(1200, 1600);
-            wand.strip_image().expect("Strip");
-            let to_write = wand.write_image_blob(extension).expect("Write worked");
             println!("data len: {}", to_write.len());
             let builder = ZipEntryBuilder::new(filename.clone(), Compression::Deflate);
             tmp_zip