README.md
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6
7# fs-err
8
9[](https://crates.io/crates/fs-err)
10[](https://github.com/andrewhickman/fs-err/actions?query=workflow%3ACI)
11
12fs-err is a drop-in replacement for [`std::fs`][std::fs] that provides more
13helpful messages on errors. Extra information includes which operations was
14attmpted and any involved paths.
15
16## Error Messages
17
18Using [`std::fs`][std::fs], if this code fails:
19
20```rust
21let file = File::open("does not exist.txt")?;
22```
23
24The error message that Rust gives you isn't very useful:
25
26```txt
27The system cannot find the file specified. (os error 2)
28```
29
30...but if we use fs-err instead, our error contains more actionable information:
31
32```txt
33failed to open file `does not exist.txt`
34 caused by: The system cannot find the file specified. (os error 2)
35```
36
37## Usage
38
39fs-err's API is the same as [`std::fs`][std::fs], so migrating code to use it is easy.
40
41```rust
42// use std::fs;
43use fs_err as fs;
44
45let contents = fs::read_to_string("foo.txt")?;
46
47println!("Read foo.txt: {}", contents);
48
49```
50
51fs-err uses [`std::io::Error`][std::io::Error] for all errors. This helps fs-err
52compose well with traits from the standard library like
53[`std::io::Read`][std::io::Read] and crates that use them like
54[`serde_json`][serde_json]:
55
56```rust
57use fs_err::File;
58
59let file = File::open("my-config.json")?;
60
61// If an I/O error occurs inside serde_json, the error will include a file path
62// as well as what operation was being performed.
63let decoded: Vec<String> = serde_json::from_reader(file)?;
64
65println!("Program config: {:?}", decoded);
66
67```
68
69[std::fs]: https://doc.rust-lang.org/stable/std/fs/
70[std::io::Error]: https://doc.rust-lang.org/stable/std/io/struct.Error.html
71[std::io::Read]: https://doc.rust-lang.org/stable/std/io/trait.Read.html
72[serde_json]: https://crates.io/crates/serde_json
73
74## License
75
76Licensed under either of
77
78* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)
79* MIT license ([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT)
80
81at your option.
82
83### Contribution
84
85Unless you explicitly state otherwise, any contribution intentionally
86submitted for inclusion in the work by you, as defined in the Apache-2.0
87license, shall be dual licensed as above, without any additional terms or
88conditions.
89
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