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https://github.com/rust-lang-nursery/rust-cookbook
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Merge pull request #79 from budziq/reqwest_temp
Implemented "Download a file to a temporary directory" example
This commit is contained in:
David Tolnay
GitHub
commit
3fbfce6ab9
2 changed files with 74 additions and 1 deletions
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@ -25,7 +25,7 @@ community. It needs and welcomes help. For details see
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| [Generate random floating point numbers][ex-rand-float] | [![rand-badge]][rand] | [![cat-science-badge]][cat-science] |
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| [Generate random numbers within a range][ex-rand-range] | [![rand-badge]][rand] | [![cat-science-badge]][cat-science] |
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| [Generate random numbers with normal distribution][ex-rand-dist] | [![rand-badge]][rand] | [![cat-science-badge]][cat-science] |
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| [Generate random values on a custom type][ex-rand-custom] | [![rand-badge]][rand] | [![cat-science-badge]][cat-science] |
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| [Generate random values of a custom type][ex-rand-custom] | [![rand-badge]][rand] | [![cat-science-badge]][cat-science] |
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## [Encoding](encoding.html)
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@ -51,6 +51,7 @@ community. It needs and welcomes help. For details see
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| [Remove fragment identifiers and query pairs from a URL][ex-url-rm-frag] | [![url-badge]][url] | [![cat-net-badge]][cat-net] |
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| [Serialize a `Url`][ex-url-serialize] | [![url-badge]][url] [![serde-badge]][serde] | [![cat-net-badge]][cat-net] [![cat-encoding-badge]][cat-encoding]|
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| [Make a HTTP GET request after parsing a URL][ex-url-basic] | [![reqwest-badge]][reqwest] | [![cat-net-badge]][cat-net] |
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| [Download a file to a temporary directory][ex-url-download] | [![reqwest-badge]][reqwest] [![tempdir-badge]][tempdir] | [![cat-net-badge]][cat-net] [![cat-filesystem-badge]][cat-filesystem] |
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## [Application development](app.html)
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@ -117,6 +118,8 @@ Keep lines sorted.
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[std]: https://doc.rust-lang.org/std
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[syslog-badge]: https://img.shields.io/crates/v/syslog.svg?label=syslog
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[syslog]: https://docs.rs/syslog/
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[tempdir-badge]: https://img.shields.io/crates/v/tempdir.svg?label=tempdir
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[tempdir]: https://docs.rs/tempdir/
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[toml-badge]: https://img.shields.io/crates/v/toml.svg?label=toml
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[toml]: https://docs.rs/toml/
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[url-badge]: https://img.shields.io/crates/v/url.svg?label=url
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@ -146,4 +149,5 @@ Keep lines sorted.
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[ex-url-origin]: net.html#ex-url-origin
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[ex-url-rm-frag]: net.html#ex-url-rm-frag
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[ex-url-serialize]: net.html#ex-url-serialize
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[ex-url-download]: net.html#ex-url-download
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[ex-url-basic]: net.html#ex-url-basic
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69
src/net.md
69
src/net.md
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@ -9,6 +9,7 @@
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| [Remove fragment identifiers and query pairs from a URL][ex-url-rm-frag] | [![url-badge]][url] | [![cat-net-badge]][cat-net] |
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| [Serialize a `Url`][ex-url-serialize] | [![url-badge]][url] [![serde-badge]][serde] | [![cat-net-badge]][cat-net] [![cat-encoding-badge]][cat-encoding]|
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| [Make a HTTP GET request][ex-url-basic] | [![reqwest-badge]][reqwest] | [![cat-net-badge]][cat-net] |
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| [Download a file to a temporary directory][ex-url-download] | [![reqwest-badge]][reqwest] [![tempdir-badge]][tempdir] | [![cat-net-badge]][cat-net] [![cat-filesystem-badge]][cat-filesystem] |
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[ex-url-parse]: #ex-url-parse
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<a name="ex-url-parse"/>
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@ -270,10 +271,71 @@ fn run() -> Result<()> {
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quick_main!(run);
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```
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[ex-url-download]: #ex-url-download
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<a name="ex-url-download"></a>
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## Download a file to a temporary directory
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[![reqwest-badge]][reqwest] [![tempdir-badge]][tempdir] [![cat-net-badge]][cat-net] [![cat-filesystem-badge]][cat-filesystem]
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Temporary directory is created with [`TempDir::new`] and a file is synchronously
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downloaded over HTTP using [`reqwest::get`].
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Target [`File`] with name obtained from [`Response::url`] is created within [`TempDir::path`]
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and downloaded data is copied into it with [`io::copy`]. The temporary directory is implicitly removed on `run` function return.
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```rust,no_run
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#[macro_use]
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extern crate error_chain;
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extern crate reqwest;
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extern crate tempdir;
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use std::io::copy;
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use std::fs::File;
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use tempdir::TempDir;
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error_chain! {
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foreign_links {
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Io(std::io::Error);
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HttpReqest(reqwest::Error);
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}
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}
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fn run() -> Result<()> {
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// create a temp dir with prefix "example"
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let tmp_dir = TempDir::new("example")?;
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// make HTTP request for remote content
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let target = "https://www.rust-lang.org/logos/rust-logo-512x512.png";
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let mut response = reqwest::get(target)?;
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let mut dest = {
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// extract target filename from URL
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let fname = response.url()
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.path_segments()
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.and_then(|segments| segments.last())
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.and_then(|name| if name.is_empty() { None } else { Some(name) })
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.unwrap_or("tmp.bin");
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println!("file to download: '{}'", fname);
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let fname = tmp_dir.path().join(fname);
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println!("will be located under: '{:?}'", fname);
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// create file with given name inside the temp dir
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File::create(fname)?
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};
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// data is copied into the target file
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copy(&mut response, &mut dest)?;
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// tmp_dir is implicitly removed
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Ok(())
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}
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quick_main!(run);
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```
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<!-- Categories -->
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[cat-encoding-badge]: https://img.shields.io/badge/-encoding-red.svg
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[cat-encoding]: https://crates.io/categories/encoding
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[cat-filesystem-badge]: https://img.shields.io/badge/-filesystem-red.svg
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[cat-filesystem]: https://crates.io/categories/filesystem
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[cat-net-badge]: https://img.shields.io/badge/-net-red.svg
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[cat-net]: https://crates.io/categories/network-programming
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@ -283,11 +345,15 @@ quick_main!(run);
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[reqwest]: https://docs.rs/reqwest/
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[serde-badge]: https://img.shields.io/crates/v/serde.svg?label=serde
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[serde]: https://docs.rs/serde/
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[tempdir-badge]: https://img.shields.io/crates/v/tempdir.svg?label=tempdir
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[tempdir]: https://docs.rs/tempdir/
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[url-badge]: https://img.shields.io/crates/v/url.svg?label=url
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[url]: https://docs.rs/url/
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<!-- Reference -->
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[`io::copy`]: https://doc.rust-lang.org/std/io/fn.copy.html
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[`File`]: https://doc.rust-lang.org/std/fs/struct.File.html
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[`Url`]: https://docs.rs/url/1.*/url/struct.Url.html
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[`parse`]: https://docs.rs/url/1.*/url/struct.Url.html#method.parse
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[`url::Position`]: https://docs.rs/url/*/url/enum.Position.html
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@ -295,5 +361,8 @@ quick_main!(run);
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[`join`]: https://docs.rs/url/1.*/url/struct.Url.html#method.join
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[`reqwest::get`]: https://docs.rs/reqwest/*/reqwest/fn.get.html
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[`reqwest::Response`]: https://docs.rs/reqwest/*/reqwest/struct.Response.html
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[`Response::url`]: https://docs.rs/reqwest/*/reqwest/struct.Response.html#method.url
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[`read_to_string`]: https://doc.rust-lang.org/std/io/trait.Read.html#method.read_to_string
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[`String`]: https://doc.rust-lang.org/std/string/struct.String.html
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[`TempDir::new`]: https://docs.rs/tempdir/*/tempdir/struct.TempDir.html#method.new
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[`TempDir::path`]: https://docs.rs/tempdir/*/tempdir/struct.TempDir.html#method.path
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