v/examples/news_fetcher.v

59 lines
1.1 KiB
Go

// Copyright (c) 2019 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 http
import json
import sync
import time
const (
NR_THREADS = 8
)
struct Story {
title string
url string
}
struct Fetcher {
mut:
mu sync.Mutex
ids []int
cursor int
}
fn (f mut Fetcher) fetch() {
for {
f.mu.lock()
if f.cursor >= f.ids.len {
return
}
id := f.ids[f.cursor]
f.cursor++
f.mu.unlock()
resp := http.get('https://hacker-news.firebaseio.com/v0/item/${id}.json')
story := json.decode(Story, resp) or {
println('failed to decode a story')
exit(1)
}
println('#$f.cursor) $story.title | $story.url')
}
}
// Fetches top HN stories in 8 coroutines
fn main() {
resp := http.get('https://hacker-news.firebaseio.com/v0/topstories.json')
ids := json.decode( []int, resp) or {
println('failed to fetch topstories.json')
return
}
fetcher := &Fetcher{ids: ids}
for i := 0; i < NR_THREADS; i++ {
go fetcher.fetch()
}
println(fetcher.ids)
time.sleep(5)
}