Adding ability to download image from url and then convert it

Cargo.toml

@@ -10,6 +10,6 @@ repository = "https://github.com/katsumeshi/image-base64-rs.git"
 [dependencies]
 image = "0.12.3"
 base64 = "0.4.0"
-regex = "0.2.1"
+reqwest = { version = "0.10.6", features = ["blocking"]}
 rustc-serialize = "0.3.22"
 rust-crypto =  "0.2.36"

src/lib.rs

@@ -1,22 +1,20 @@
+extern crate reqwest;
 extern crate rustc_serialize;
-extern crate regex;
 
-use std::fs::File;
+use reqwest::blocking;
 use rustc_serialize::base64::{FromBase64, ToBase64, MIME};
-use rustc_serialize::hex::{ToHex};
-use regex::Regex;
+use rustc_serialize::hex::ToHex;
+use std::fs::File;
 use std::io::Read;
 use std::string::String;
 
 pub fn get_file_type(hex: &str) -> &str {
-    if Regex::new(r"^ffd8ffe0").unwrap().is_match(hex) { 
-        return "jpeg" 
-    } else if Regex::new(r"^89504e47").unwrap().is_match(hex) {  
-        return "png" 
-    } else if Regex::new(r"^47494638").unwrap().is_match(hex) { 
-        return "gif"
-    } 
-    panic!("invalid file type")
+    match &hex[..8] {
+        r"ffd8ffe0" => "jpeg",
+        r"89504e47" => "png",
+        r"47494638" => "gif",
+        _ => panic!("invalid file type"),
+    }
 }
 
 pub fn to_base64(path: &str) -> String {
@@ -25,12 +23,29 @@ pub fn to_base64(path: &str) -> String {
     let _ = file.read_to_end(&mut vec);
     let base64 = vec.to_base64(MIME);
     let hex = vec.to_hex();
-    return format!("data:image/{};base64,{}", get_file_type(&hex), base64.replace("\r\n", ""));
+    return format!(
+        "data:image/{};base64,{}",
+        get_file_type(&hex),
+        base64.replace("\r\n", "")
+    );
 }
 
 pub fn from_base64(base64: String) -> Vec<u8> {
-    let offset = base64.find(',').unwrap_or(base64.len())+1;
+    let offset = base64.find(',').unwrap_or(base64.len()) + 1;
     let mut value = base64;
     value.drain(..offset);
-    return value.from_base64().unwrap();
-}
+    value.from_base64().unwrap()
+}
+
+pub fn from_url(image_url: &str) -> String {
+    let result = reqwest::blocking::get(image_url).unwrap().bytes().unwrap();
+
+    let base64 = result.to_base64(MIME);
+    let hex = result.to_hex();
+
+    format!(
+        "data:image/{};base64,{}",
+        get_file_type(&hex),
+        base64.replace("\r\n", "")
+    )
+}

tests/test.rs

@@ -1,5 +1,4 @@
 extern crate rustc_serialize;
-extern crate regex;
 extern crate crypto;
 extern crate image_base64;
 
@@ -112,4 +111,42 @@ fn vector_as_u8_4_array(vector: Vec<u8>) -> [u8;4] {
         *place = *element;
     }
     arr
-}
+}
+
+#[test]
+fn png_url_to_base64() {
+    url_to_base64("png");
+}
+
+#[test]
+fn jpg_url_to_base64() {
+    url_to_base64("jpg");
+}
+
+#[test]
+fn gif_url_to_base64() {
+    url_to_base64("gif");
+}
+
+fn url_to_base64(file_type: &str) {
+    let result = image_base64::from_url(
+        format!(
+            "{}{}",
+            "https://raw.githubusercontent.com/katsumeshi/image-base64-rs/master/res/nyan.",
+            file_type
+        )
+        .as_ref(),
+    );
+
+    let mut file = match File::open(format!("res/{}_data", file_type)) {
+        Err(why) => panic!("couldn't open {}", why),
+        Ok(file) => file,
+    };
+    let mut buffer = String::new();
+    match file.read_to_string(&mut buffer) {
+        Err(why) => panic!("couldn't read {}", why),
+        Ok(_) => {}
+    }
+
+    assert_eq!(result, buffer);
+}