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//! The main module that fetches html code and scrapes the more information href link and displays
//! it on stdout.

use reqwest::header::{HeaderMap, CONTENT_TYPE, REFERER, USER_AGENT};
use scraper::{Html, Selector};
use std::{println, time::Duration};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // A map that holds various request headers
    let mut headers = HeaderMap::new();
    headers.insert(
        USER_AGENT,
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0"
            .parse()?, // --> (1)
    );
    headers.insert(REFERER, "https://google.com/".parse()?); // --> (1)
    headers.insert(CONTENT_TYPE, "application/x-www-form-urlencoded".parse()?); // --> (1)

    // A blocking request call that fetches the html text from the example.com site.
    let html_results = reqwest::blocking::Client::new()
        .get("https://example.com/")
        .timeout(Duration::from_secs(30))
        .headers(headers)
        .send()? // --> (2)
        .text()?; // --> (2)

    // Parse the recieved html text to html for scraping.
    let document = Html::parse_document(&html_results);

    // Initialize a new selector for scraping more information href link.
    let more_info_href_link_selector = Selector::parse("div>p>a")?; // --> (3)

    // Scrape the more information href link.
    let more_info_href_link = document
        .select(&more_info_href_link_selector)
        .next()
        .unwrap()
        .value()
        .attr("href")
        .unwrap();

    // Print the more information link.
    println!("More information link: {}", more_info_href_link);

    Ok(())
}

[dependencies]
scraper="0.16.0"
error-stack="0.3.1"
reqwest = {version="0.11.18",features=["blocking"]}

fn main() {
    match caller("4", "6") {
        Ok(sum) => println!("Sum is: {}", sum),
        Err(error) => println!("{}", error),
    }
}

fn sum_numbers_from_string(
    number_x_as_string: &str,
    number_y_as_string: &str,
) -> Result<u32, Box<dyn std::error::Error>> {
    let number_x: u32 = number_x_as_string.parse()?; 
    let number_y: u32 = number_y_as_string.parse()?;

    println!("This code is being executed!! and the code below will also be executed!! :)");

    Ok(number_x + number_y)
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let number_x: u32 = "4".parse()?;
    let number_y: u32 = "6".parse()?;

    println!("This code is being executed!! and the code below will also be executed!! :)");

    println!("Sum is: {}", number_x + number_y);

    Ok(())
}

#[derive(Debug)]
enum ScraperError {
    InvalidHeaderMapValue,
    RequestError,
    SelectorError,
}

impl fmt::Display for ScraperError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ScraperError::InvalidHeaderMapValue => {
                write!(f, "Invalid header map value provided")
            }
            ScraperError::RequestError => {
                write!(f, "Error occurred while requesting data from the webpage")
            }
            ScraperError::SelectorError => {
                write!(f, "An error occured while initializing new Selector")
            }
        }
    }
}

impl Context for ScraperError {}

fn main() -> Result<(), ScraperError> {
    // A map that holds various request headers
    let mut headers = HeaderMap::new();
    headers.insert(
        USER_AGENT,
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?, // --> (1)
    );
    headers.insert(
        REFERER,
        "https://google.com/"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?,
    ); // --> (1)
    headers.insert(
        CONTENT_TYPE,
        "application/x-www-form-urlencoded"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?,
    ); // --> (1)

    // A blocking request call that fetches the html text from the example.com site.
    let html_results = reqwest::blocking::Client::new()
        .get("https://example.com/")
        .timeout(Duration::from_secs(30))
        .headers(headers)
        .send()
        .into_report()
        .change_context(ScraperError::RequestError)? // --> (2)
        .text()
        .into_report()
        .change_context(ScraperError::RequestError)?; // --> (2)

    // Parse the recieved html text to html for scraping.
    let document = Html::parse_document(&html_results);

    // Initialize a new selector for scraping more information href link.
    let more_info_href_link_selector = Selector::parse("div>p>a$")
        .into_report()
        .change_context(ScraperError::SelectorError)?; // --> (3)

    // Scrape the more information href link.
    let more_info_href_link = document
        .select(&more_info_href_link_selector)
        .next()
        .unwrap()
        .value()
        .attr("href")
        .unwrap();

    // Print the more information link.
    println!("More information link: {}", more_info_href_link);

    Ok(())
}

//! The main module that fetches html code and scrapes the more information href link and displays
//! it on stdout.

use core::fmt;
use error_stack::{Context, IntoReport, Result, ResultExt};
use reqwest::header::{HeaderMap, CONTENT_TYPE, REFERER, USER_AGENT};
use scraper::{Html, Selector};
use std::{println, time::Duration};

#[derive(Debug)]
enum ScraperError {
    InvalidHeaderMapValue,
    RequestError,
    SelectorError,
}

impl fmt::Display for ScraperError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ScraperError::InvalidHeaderMapValue => {
                write!(f, "Invalid header map value provided")
            }
            ScraperError::RequestError => {
                write!(f, "Error occurred while requesting data from the webpage")
            }
            ScraperError::SelectorError => {
                write!(f, "An error occured while initializing new Selector")
            }
        }
    }
}

impl Context for ScraperError {}

fn main() -> Result<(), ScraperError> {
    // A map that holds various request headers
    let mut headers = HeaderMap::new();
    headers.insert(
        USER_AGENT,
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?, // --> (1)
    );
    headers.insert(
        REFERER,
        "https://google.com/"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?,
    ); // --> (1)
    headers.insert(
        CONTENT_TYPE,
        "application/x-www-form-urlencoded"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?,
    ); // --> (1)

    // A blocking request call that fetches the html text from the example.com site.
    let html_results = reqwest::blocking::Client::new()
        .get("https://example.com/")
        .timeout(Duration::from_secs(30))
        .headers(headers)
        .send()
        .into_report()
        .change_context(ScraperError::RequestError)? // --> (2)
        .text()
        .into_report()
        .change_context(ScraperError::RequestError)?; // --> (2)

    // Parse the recieved html text to html for scraping.
    let document = Html::parse_document(&html_results);

    // Initialize a new selector for scraping more information href link.
    let more_info_href_link_selector = Selector::parse("div>p>a$")
        .into_report()
        .change_context(ScraperError::SelectorError)?; // --> (3)

    // Scrape the more information href link.
    let more_info_href_link = document
        .select(&more_info_href_link_selector)
        .next()
        .unwrap()
        .value()
        .attr("href")
        .unwrap();

    // Print the more information link.
    println!("More information link: {}", more_info_href_link);

    Ok(())
}

error[E0599]: the method `into_report` exists for enum `Result<Selector, SelectorErrorKind<'_>>`, but its trait bounds were not satisfied
    |
   ::: /home/destruct/.cargo/registry/src/github.com-1ecc6299db9ec823/error-stack-0.3.1/src/report.rs:249:1
    |
249 |   pub struct Report<C> {
    |   -------------------- doesn't satisfy `_: From<SelectorErrorKind<'_>>`
    |
   ::: /home/destruct/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/result.rs:503:1
    |
503 |   pub enum Result<T, E> {
    |   --------------------- doesn't satisfy `_: IntoReport`
   --> src/main.rs:77:10
    |
76  |       let more_info_href_link_selector = Selector::parse("div>p>a$")
    |  ________________________________________-
77  | |         .into_report()
    | |_________-^^^^^^^^^^^
    |
    = note: the following trait bounds were not satisfied:
            `error_stack::Report<SelectorErrorKind<'_>>: From<SelectorErrorKind<'_>>`
            which is required by `Result<Selector, SelectorErrorKind<'_>>: IntoReport`

For more information about this error, try `rustc --explain E0599`.
error: could not compile `error-stack-blog` due to previous error

let more_info_href_link_selector = Selector::parse("div>p>a$")
    .map_err(|_| Report::new(ScraperError::SelectorError))
    .attach_printable_lazy(|| "invalid CSS selector provided")?; // --> (3)

//! The main module that fetches html code and scrapes the more information href link and displays
//! it on stdout.

use core::fmt;
use error_stack::{Context, IntoReport, Report, Result, ResultExt};
use reqwest::header::{HeaderMap, CONTENT_TYPE, REFERER, USER_AGENT};
use scraper::{Html, Selector};
use std::{println, time::Duration};

#[derive(Debug)]
enum ScraperError {
    InvalidHeaderMapValue,
    RequestError,
    SelectorError,
}

impl fmt::Display for ScraperError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ScraperError::InvalidHeaderMapValue => {
                write!(f, "Invalid header map value provided")
            }
            ScraperError::RequestError => {
                write!(f, "Error occurred while requesting data from the webpage")
            }
            ScraperError::SelectorError => {
                write!(f, "An error occured while initializing new Selector")
            }
        }
    }
}

impl Context for ScraperError {}

fn main() -> Result<(), ScraperError> {
    // A map that holds various request headers
    let mut headers = HeaderMap::new();
    headers.insert(
        USER_AGENT,
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?, // --> (1)
    );
    headers.insert(
        REFERER,
        "https://google.com/"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?,
    ); // --> (1)
    headers.insert(
        CONTENT_TYPE,
        "application/x-www-form-urlencoded"
            .parse()
            .into_report()
            .change_context(ScraperError::InvalidHeaderMapValue)?,
    ); // --> (1)

    // A blocking request call that fetches the html text from the example.com site.
    let html_results = reqwest::blocking::Client::new()
        .get("https://example.com/")
        .timeout(Duration::from_secs(30))
        .headers(headers)
        .send()
        .into_report()
        .change_context(ScraperError::RequestError)? // --> (2)
        .text()
        .into_report()
        .change_context(ScraperError::RequestError)?; // --> (2)

    // Parse the recieved html text to html for scraping.
    let document = Html::parse_document(&html_results);

    // Initialize a new selector for scraping more information href link.
    let more_info_href_link_selector = Selector::parse("div>p>a$")
        .map_err(|_| Report::new(ScraperError::SelectorError))
        .attach_printable_lazy(|| "invalid CSS selector provided")?; // --> (3)

    // Scrape the more information href link.
    let more_info_href_link = document
        .select(&more_info_href_link_selector)
        .next()
        .unwrap()
        .value()
        .attr("href")
        .unwrap();

    // Print the more information link.
    println!("More information link: {}", more_info_href_link);

    Ok(())
}

Error: An error occured while initializing new Selector
├╴at src/main.rs:77:22
╰╴invalid CSS selector provided