main.rs

use std::collections::HashMap;

use futures::{stream, StreamExt};
use reqwest::Client;
use serde::{Deserialize, Serialize};
use std::error::Error;

#[derive(Serialize, Deserialize, Debug)]
struct ProjectsItem {
    hash_id: String,
}

type ProjectsData = Vec<ProjectsItem>;

#[derive(Serialize, Deserialize, Debug)]
struct ProjectsResponse {
    data: ProjectsData
}


#[derive(Serialize, Deserialize, Debug)]
struct ProjectAsset {
    image_url: String,
}

type ProjectAssets = Vec<ProjectsItem>;

#[derive(Serialize, Deserialize, Debug)]
struct ProjectResponse {
    assets: ProjectAssets
}

const PARALLEL_REQUESTS: usize = 2;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let username = "anniehexample";
    let projects_url = format!("https://example.com/users/{}/projects.json", username);

    let client = Client::new();

    let projects = client.get(&projects_url)
        .send()
        .await?
        .json::<ProjectsResponse>()
        .await?;

    let mut stream = futures::stream::FuturesUnordered::new();

    let bodies = stream::iter(projects.data)
        .map(|project| {
            let client = &client;
            async move {
                client.get(&format!("https://example.com/projects/{}.json", project.hash_id))
                    .send()
                    .await?
                    .json::<ProjectsResponse>()
                    .await
            }
        })
        .buffer_unordered(PARALLEL_REQUESTS)
        .await;


    println!("{:#?}", bodies);
    Ok(())
}