ソフトウェアエンジニアの技術ブログ：Software engineer tech blog

fn get_chunks(num_ranges: u32, length: u32) {
    let max_number = 10_i32.pow(length) as u32;

    let mut chunk_starts = Vec::new();
    for i in 0..num_ranges {
        chunk_starts.push(max_number / num_ranges * i )
    }

    let mut chunk_ends:Vec<u32> = Vec::new();
    for i in &chunk_starts[1..] {
        chunk_ends.push(i - 1);
    }
    chunk_ends.push(max_number);

    let mut chunks = HashMap::new();
    for i in 0..chunk_starts.len() {
        chunks.insert(chunk_starts[i], chunk_ends[i]);
    }
    println!("{:?}", chunks);
}

get_chunks(5, 2);
{40: 59, 60: 79, 20: 39, 80: 100, 0: 19}

なるほどね

num_cpus = “1.0”

fn main() {

    let num = num_cpus::get();
    println!("{}", num);

}

存在しうる全ての値を計算する。
桁数が増えれば増えるほど、処理時間がかかる。6桁で約1秒(1000ms)くらいかかる。

use sha2::{Digest, Sha256};
use std::time;

fn main() {
    let password: String = "13225".to_string(); 
    let length = password.chars().count() as u32;

    let crypto_hash: String = get_crypto_hash(password);
    crack_password(crypto_hash, length);
}

fn get_combinations(length: u32) -> Vec<String> {
    let mut combinations: Vec<String> = Vec::new();
    let min_number = 0;
    let max_number = 10_i32.pow(length);

    for i in min_number..max_number {
        let str_num: String = i.to_string();
        let zeros: String = "0".repeat((length - str_num.chars().count() as u32).try_into().unwrap());
        combinations.push(format!("{}{}", zeros, str_num));
    }
    return combinations;
}

fn get_crypto_hash(password: String) -> String {
    let sha = Sha256::digest(password);
    hex::encode(sha).to_string()
}

fn check_password(expected_crypto_hash: String, possible_password: String) -> bool {
    let actual_crypto_hash = get_crypto_hash(possible_password);
    return expected_crypto_hash == actual_crypto_hash
}

fn crack_password(crypto_hash: String, length: u32) {
    println!("Processing number combinations sequentially");
    let start_time = time::Instant::now();
    let combinations: Vec<String> = get_combinations(length);
    for combination in combinations {
        if check_password(crypto_hash.clone(), combination.clone()) {
            println!("PASSWORD CRACKED:{}", combination);
            break;
        }
    }
    println!("PROCESS TIME: {:?}", start_time.elapsed());
}

Compiling parallel v0.1.0 (/home/vagrant/dev/rust/parallel)
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.16s
Running `target/debug/parallel`
Processing number combinations sequentially
PASSWORD CRACKED:13225
PROCESS TIME: 97.760443ms

println!("{}", power(3));

//

fn power(x: u32) -> i32 {
    10_i32.pow(x)
}

Compiling sample v0.1.0 (/home/vagrant/dev/rust/sample)
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.19s
Running `target/debug/sample`
1000

値を整形せずに、そのまま返しています。

async fn handle_service(extract::Json(payload): extract::Json<Service>) -> Json<Service>{

    println!("{:?}", payload);
    Json(payload)
}

curl -X POST -H “Content-Type: application/json” -d “{\”version\”:\”1\”,\”nonce\”:\”1482680747\”,\”connections\”:21}” 127.0.0.1:3000/service
{“version”:”1″,”nonce”:”1482680747″,”connections”:21}

なるほどー

IPを返却するサイトからIPアドレスを取得します。
httpbinにreqwest::getすると、String型で返却されるので、serde_jsonを使ってIpの構造体に変換しています。

use reqwest::Client;
use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, Debug)]
struct Ip {
    origin: String,
}

#[tokio::main]
async fn main() {
    let _ = get_ip().await;
}

// get ip
async fn get_ip() -> Result<(), Box<dyn std::error::Error>> {

    let ip: Ip = serde_json::from_str(&reqwest::get("https://httpbin.org/ip")
        .await?
        .text()
        .await?)?;
    
    println!("ip = {:?}", ip.origin);
    Ok(())
}

Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.08s
Running `target/debug/sample`
ip = “***.***.*.***”

うーむ、なんだかな〜

map.get(&target) != None でチェックできる。

    let mut holder: HashMap<String, String> = HashMap::new();

    holder.insert("yamada".to_string(), "A".to_string());
    holder.insert("sato".to_string(), "B".to_string());
    holder.insert("tanaka".to_string(), "C".to_string());

    for (name, item) in &holder {
        println!("{}:{}", name, item);
    }

    let target = "yamada".to_string();
    if holder.get(&target) != None {
        println!("{}", holder["yamada"]);
    }

Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.33s
Running `target/debug/my_web_app`
yamada:A
tanaka:C
sato:B
A

pythonのように　target in map ではチェックできない。
なるほど…

async fn handle_logout()-> impl IntoResponse{

    let tera = tera::Tera::new("templates/*").unwrap();

    let mut context = tera::Context::new();
    context.insert("title", "Index page");
    context.insert("data", "hoge");

    let output = tera.render("index.html", &context);
    let cookie:String = format!("session_token=_");
    let headers = AppendHeaders(vec![("Set-Cookie", cookie)]);
    (headers, axum::response::Html(output.unwrap()))
}

特にコメントなし。
さー次行こう^^