项目实战

实战5：实现BTC价格转换工具

今天我们来开发一个简单的BTC实时价格转换工具。

我们首先创建一个目录：

cargo new btc_converter

我们用TDD方式来开发。

然后我们先写一些测试代码。

在src/main.rs下面，增加代码如下：

#[cfg(test)]

mod tests {

    use super::*;

    #[test]

    fn test_convert_success() {

        match convert_btc(1.2, "BTC", "USD") {

            Ok(_) => assert!(true),

            Err(_) => assert!(false),

        }

    }

    #[test]

    fn test_convert_success2() {

        match convert_btc(2.1, "BTC", "MKD") {

            Ok(_) => assert!(true),

            Err(_) => assert!(false),

        }

    }

    #[test]

    fn test_convert_error_wrong_from() {

        match convert_btc(1.2, "wrongvalue", "USD") {

            Ok(_) => assert!(false),

            Err(_) => assert!(true),

        }

    }

    #[test]

    fn test_convert_error_wrong_to() {

        match convert_btc(1.2, "USD", "wrongvalue") {

            Ok(_) => assert!(false),

            Err(_) => assert!(true),

        }

    }

}

我们运行命令：

cargo test

结果肯定是不通过。

我现在我们来增加核心业务代码：

const API_URL: &str = "https://apiv2.bitcoinaverage.com/convert/global";

//错误信息

#[derive(From, Display, Debug)]

enum BtcError {

    ApiError,

    Reqwest(reqwest::Error),

}

//响应信息结构体

#[derive(Deserialize, Debug)]

struct BtcResponse {

    time: String,

    success: bool,

    price: f64,

}

//价格转换，直接调用相关API

fn convert_btc(amount: f64, from: &str, to: &str) -> Result<BtcResponse, BtcError> {

    use BtcError::*;

    println!("---convert_btc-----{:?},{:?}", from, to);

    let client = reqwest::Client::new();

    let request =

        client

            .get(API_URL)

            .query(&[("from", from), ("to", to), ("amount", &amount.to_string())]);

    let response_result: BtcResponse = request.send()?.json()?;

    if !response_result.success {

        return Err(ApiError);

    }

    return Ok(response_result);

}

然后，我们再跑一下测试用例。

现在应该都通过了。

当然我们要引用相关包：

[dependencies]

reqwest = "0.9.12"

serde_derive = "1.0.89"

serde = "1.0.89"

serde_json = "1.0.39"

structopt = "0.2.15"

derive_more = "0.14.0"

src/main.rs完整代码如下：

#[macro_use]

extern crate serde_derive;

#[macro_use]

extern crate derive_more;

use reqwest;

use std::process::exit;

use structopt::StructOpt;

fn main() {

    let opt = Opt::from_args();

    let response = match convert_btc(opt.amount, &opt.from, &opt.to) {

        Ok(value) => value,

        Err(e) => {

            println!("A error occurred when try to get value from api");

            if opt.verbose {

                println!("Message: {} - Details: {:?}", e, e);

            }

            exit(1);

        }

    };

    if opt.silent {

        println!("{}", response.price);

    } else {

        println!("{} {}", response.price, &opt.to);

    }

}

const API_URL: &str = "https://apiv2.bitcoinaverage.com/convert/global";

//错误信息

#[derive(From, Display, Debug)]

enum BtcError {

    ApiError,

    Reqwest(reqwest::Error),

}

//响应信息结构体

#[derive(Deserialize, Debug)]

struct BtcResponse {

    time: String,

    success: bool,

    price: f64,

}

#[derive(Debug, StructOpt)]

#[structopt(

    name = "btc_converter",

    about = "Get value of a btc value to a currency"

)]

struct Opt {

    /// Set amount to convert to a currency or from a currency

    #[structopt(default_value = "1")]

    amount: f64,

    /// Set the initial currency of

    #[structopt(short = "f", long = "from", default_value = "BTC")]

    from: String,

    /// Set the final currency to convert

    #[structopt(short = "t", long = "to", default_value = "USD")]

    to: String,

    /// Silent information about currency result

    #[structopt(short = "s", long = "silent")]

    silent: bool,

    /// Verbose errors

    #[structopt(short = "v", long = "verbose")]

    verbose: bool,

}

fn convert_btc(amount: f64, from: &str, to: &str) -> Result<BtcResponse, BtcError> {

    use BtcError::*;

    println!("---convert_btc-----{:?},{:?}", from, to);

    let client = reqwest::Client::new();

    let request =

        client

            .get(API_URL)

            .query(&[("from", from), ("to", to), ("amount", &amount.to_string())]);

    let response_result: BtcResponse = request.send()?.json()?;

    if !response_result.success {

        return Err(ApiError);

    }

    return Ok(response_result);

}

#[cfg(test)]

mod tests {

    use super::*;

    #[test]

    fn test_convert_success() {

        match convert_btc(1.2, "BTC", "USD") {

            Ok(_) => assert!(true),

            Err(_) => assert!(false),

        }

    }

    #[test]

    fn test_convert_success2() {

        match convert_btc(2.1, "BTC", "MKD") {

            Ok(_) => assert!(true),

            Err(_) => assert!(false),

        }

    }

    #[test]

    fn test_convert_error_wrong_from() {

        match convert_btc(1.2, "wrongvalue", "USD") {

            Ok(_) => assert!(false),

            Err(_) => assert!(true),

        }

    }

    #[test]

    fn test_convert_error_wrong_to() {

        match convert_btc(1.2, "USD", "wrongvalue") {

            Ok(_) => assert!(false),

            Err(_) => assert!(true),

        }

    }

}

API地址：

https://apiv2.bitcoinaverage.com

以上，希望对你有用。

如果遇到什么问题，欢迎加入：rust新手群，在这里我可以提供一些简单的帮助，加微信：360369487，注明：博客园+rust

巴特西

[易学易懂系列|rustlang语言|零基础|快速入门|（28）|实战5：实现BTC价格转换工具]

实战5：实现BTC价格转换工具

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