add example to use Easy2 in downloading and uploading files

examples/file_download_upload.rs

@@ -0,0 +1,163 @@
+/// This is an example how to use Easy2 to download a file.
+/// Can able to resume a download and control download speed.
+use std::{
+    fs::{self, File, OpenOptions},
+    io::{Read, Seek, SeekFrom, Write},
+    path::PathBuf,
+};
+
+use curl::easy::{Easy2, Handler, ReadError, WriteError};
+
+#[derive(Clone)]
+enum Collector {
+    File(PathBuf, usize),
+    Ram(Vec<u8>),
+}
+
+impl Handler for Collector {
+    fn write(&mut self, data: &[u8]) -> Result<usize, WriteError> {
+        match self {
+            Collector::File(download_path, _size) => {
+                println!("File chunk size: {}", data.len());
+                let mut file = OpenOptions::new()
+                    .create(true)
+                    .append(true)
+                    .open(download_path)
+                    .map_err(|e| {
+                        eprintln!("{}", e);
+                        WriteError::Pause
+                    })?;
+
+                file.write_all(data).map_err(|e| {
+                    eprintln!("{}", e);
+                    WriteError::Pause
+                })?;
+                Ok(data.len())
+            }
+            Collector::Ram(container) => {
+                container.extend_from_slice(data);
+                Ok(data.len())
+            }
+        }
+    }
+
+    fn read(&mut self, data: &mut [u8]) -> Result<usize, ReadError> {
+        match self {
+            Collector::File(path, size) => {
+                let mut file = File::open(path).map_err(|e| {
+                    eprintln!("{}", e);
+                    ReadError::Abort
+                })?;
+
+                // Seek to the desired offset
+                file.seek(SeekFrom::Start(*size as u64)).map_err(|e| {
+                    eprintln!("{}", e);
+                    ReadError::Abort
+                })?;
+
+                let read_size = file.read(data).map_err(|e| {
+                    eprintln!("{}", e);
+                    ReadError::Abort
+                })?;
+                println!("Read Size: {}", read_size);
+
+                // Update this so that we could seek succeding blocks of data from the file
+                *size += read_size;
+
+                Ok(read_size)
+            }
+            Collector::Ram(_) => Ok(0),
+        }
+    }
+}
+
+impl Collector {
+    fn get_response_body(&self) -> Option<Vec<u8>> {
+        match self {
+            Collector::File(_, _) => None,
+            Collector::Ram(container) => Some(container.clone()),
+        }
+    }
+}
+
+fn example_file_download() {
+    // File Download
+    let target_path = PathBuf::from("<SAVE DOWNLOADED FILE HERE>");
+    let collector = Collector::File(target_path.clone(), 0);
+    let mut easy2 = Easy2::new(collector);
+
+    easy2
+        .url("<INPUT YOUR TARGET DOWNLOAD LOCATION HERE>")
+        .unwrap();
+    easy2.get(true).unwrap();
+    // Download the actual file from actual location
+    easy2.follow_location(true).unwrap();
+    // Setting of download speed control in bytes per second
+    easy2.max_recv_speed(2000).unwrap();
+    // Can resume download by giving a byte offset
+    easy2.resume_from(0).unwrap();
+    easy2.perform().unwrap();
+
+    let status_code = easy2.response_code().unwrap();
+    let response_body = easy2.get_ref().get_response_body().take();
+    let content_type = easy2.content_type();
+
+    eprintln!("Status Code: {}", status_code);
+    eprintln!("content-type: {:?}", content_type);
+    eprintln!("Response Body: {:?}", response_body);
+
+    let file = fs::metadata(target_path.clone()).unwrap();
+    assert!(file.len() != 0);
+}
+
+fn example_response_as_body() {
+    // Get Response as Body
+    let collector = Collector::Ram(Vec::new());
+    let mut easy2 = Easy2::new(collector);
+
+    easy2
+        .url("<INPUT YOUR TARGET DOWNLOAD LOCATION HERE>")
+        .unwrap();
+    easy2.get(true).unwrap();
+    easy2.perform().unwrap();
+
+    let status_code = easy2.response_code().unwrap();
+    let response_body = easy2.get_ref().get_response_body().take();
+    let content_type = easy2.content_type();
+
+    eprintln!("Status Code: {}", status_code);
+    eprintln!("content-type: {:?}", content_type);
+    eprintln!("Response Body: {:?}", response_body);
+}
+
+fn example_file_upload() {
+    let target_path = PathBuf::from("<SOURCE FILE PATH TO BE UPLOADED HERE>");
+    let file_size = fs::metadata(target_path.clone()).unwrap().len();
+
+    let collector = Collector::File(target_path.clone(), 0);
+    let mut easy2 = Easy2::new(collector);
+
+    easy2
+        .url("<INPUT YOUR TARGET UPLOAD LOCATION HERE>")
+        .unwrap();
+    easy2.in_filesize(file_size).unwrap();
+    easy2.upload(true).unwrap();
+    easy2.perform().unwrap();
+
+    let status_code = easy2.response_code().unwrap();
+    let response_body = easy2.get_ref().get_response_body().take();
+    let content_type = easy2.content_type();
+
+    eprintln!("Status Code: {}", status_code);
+    eprintln!("content-type: {:?}", content_type);
+    eprintln!("Response Body: {:?}", response_body);
+
+    let file = fs::metadata(target_path.clone()).unwrap();
+    assert!(file.len() != 0);
+}
+
+fn main() {
+    example_file_download();
+    example_response_as_body();
+    example_file_upload();
+}