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v/examples/news_fetcher.v

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V

// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
import net.http
import json
import sync.pool
struct Story {
title string
url string
}
fn worker_fetch(p &pool.PoolProcessor, cursor int, worker_id int) voidptr {
id := p.get_item<int>(cursor)
resp := http.get('https://hacker-news.firebaseio.com/v0/item/${id}.json') or {
println('failed to fetch data from /v0/item/${id}.json')
return pool.no_result
}
story := json.decode(Story, resp.text) or {
println('failed to decode a story')
return pool.no_result
}
println('# $cursor) $story.title | $story.url')
return pool.no_result
}
// Fetches top HN stories in parallel, depending on how many cores you have
fn main() {
resp := http.get('https://hacker-news.firebaseio.com/v0/topstories.json') or {
println('failed to fetch data from /v0/topstories.json')
return
}
ids := json.decode([]int, resp.text) or {
println('failed to decode topstories.json')
return
}#[0..10]
mut fetcher_pool := pool.new_pool_processor(
callback: worker_fetch
)
// Note: if you do not call set_max_jobs, the pool will try to use an optimal
// number of threads, one per each core in your system, which in most
// cases is what you want anyway... You can override the automatic choice
// by setting the VJOBS environment variable too.
// fetcher_pool.set_max_jobs( 4 )
fetcher_pool.work_on_items(ids)
}