87 lines
2.1 KiB
Markdown
87 lines
2.1 KiB
Markdown
# Vet
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Arbitrary type validation.
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## Usage
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Add a dependency entry in `Cargo.toml`.
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```toml
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[dependencies]
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vet = "0.1"
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```
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Implement the `Vet` trait on your type.
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```rust
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use vet::{Valid, Vet};
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// A valid username consists of between 3 and 32 alphanumeric characters
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#[derive(Debug)]
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struct Username(String);
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#[derive(Debug, PartialEq)]
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enum InvalidUsername {
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TooShort, // Under 3 characters
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TooLong, // Over 3 characters
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InvalidChar, // Contains non-alphanumeric character
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}
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impl Vet for Username {
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type Error = InvalidUsername;
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// Arbitrary logic to validate the Username type
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fn is_valid(&self) -> Result<(), Self::Error> {
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if self.0.len() < 3 {
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return Err(Self::Error::TooShort);
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}
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if self.0.len() > 32 {
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return Err(Self::Error::TooLong);
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}
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if self.0.chars().any(|c| !c.is_alphanumeric()) {
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return Err(Self::Error::InvalidChar);
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}
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Ok(())
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}
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}
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```
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`Valid`-wrapped types provide safety guarantees about their contents.
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```rust
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fn main() {
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let args: Vec<String> = env::args().collect();
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let username: Username = Username(args[1].clone());
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let username: Result<Valid<Username>, InvalidUsername> = username.vet();
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match username {
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Ok(n) => create_account(n),
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Err(e) => eprintln!("Invalid username: {:?}", e),
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}
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}
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// Any `Valid<Username>` passed is guaranteed to be 3-32 alphanumeric characters.
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fn create_account(username: Valid<Username>) {
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let username = username.into_inner(); // Unwrap
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println!("Account {:?} created", username);
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}
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```
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## License
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Licensed under either of
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- Apache License, Version 2.0 ([license-apache.txt](license-apache.txt) or
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http://www.apache.org/licenses/LICENSE-2.0)
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- MIT license ([license-mit.txt](license-mit.txt) or
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http://opensource.org/licenses/MIT)
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at your option.
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## Contribution
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Unless you explicitly state otherwise, any contribution intentionally submitted
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for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
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dual licensed as above, without any additional terms or conditions.
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