Rust Program: Interacting with Web Service for Authentication & Data retrieval

Rust Error Propagation: Exercise-3 with Solution

Write a Rust program that interacts with a web service, performing authentication and data retrieval, propagating errors.

Sample Solution:

Rust Code:

use reqwest; // Import the reqwest crate for making HTTP requests
use std::error::Error; // Import the Error trait for error handling

// Function to perform authentication and retrieve data from the web service
fn retrieve_data(api_key: &str) -> Result> {
    // Construct the URL for the web service endpoint
    let url = format!("https://api.example.com/data?key={}", api_key);

    // Perform a GET request to the web service endpoint
    let response = reqwest::blocking::get(&url)?;

    // Check if the request was successful (status code 200 OK)
    if response.status().is_success() {
        let body = response.text()?; // Extract the response body as a string
        Ok(body) // Return the response body
    } else {
        Err(format!("Request failed with status code: {}", response.status()).into()) // Return an error message if the request was not successful
    }
}

fn main() -> Result<(), Box> {
    let api_key = "your_api_key_here"; // Replace "your_api_key_here" with your actual API key
    
    // Call the function to retrieve data from the web service
    match retrieve_data(api_key) {
        Ok(data) => println!("Received data: {}", data), // Print the received data if the request was successful
        Err(err) => eprintln!("Error retrieving data: {}", err), // Print an error message if the request failed
    }

    Ok(()) // Return Ok if the program completes successfully
}

Output:

Compiling playground v0.0.1 (/playground)
    Finished dev [unoptimized + debuginfo] target(s) in 2.78s
     Running `target/debug/playground`
Error retrieving data: error sending request for url (https://api.example.com/data?key=your_api_key_here): error trying to connect: dns error: failed to lookup address information: Temporary failure in name resolution.

Explanation:

Here is a brief explanation of the above Rust code:

• First we use the "reqwest" crate to make HTTP requests to the web service.
• The "retrieve_data()" function constructs the URL with the API key, performs a GET request to the web service endpoint, and returns the response body if the request is successful.
• The "main()" function calls "retrieve_data()" with the API key and handles any errors during the process. If the retrieval is successful, it prints the received data; otherwise, it prints an error message. Finally, it returns an 'Ok' result if the program completes successfully.

Rust Code Editor:

Previous: Rust File Operations: Copy, Move, Delete with Error handling.
Next: Rust Configuration Parser: Apply Settings & Handle errors.