v/examples/news_fetcher.v

69 lines
1.3 KiB
Go
Raw Normal View History

2019-06-23 04:21:30 +02:00
// 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.
2019-06-22 21:51:07 +02:00
import http
import json
import sync
import time
const (
NR_THREADS = 8
)
struct Story {
title string
url string
2019-06-22 21:51:07 +02:00
}
struct Fetcher {
mut:
mu sync.Mutex
ids []int
cursor int
list_id int
2019-06-22 21:51:07 +02:00
}
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()
2019-07-29 19:18:26 +02:00
resp := http.get('https://hacker-news.firebaseio.com/v0/item/${id}.json') or {
println('failed to fetch data from /v0/item/${id}.json')
exit(1)
}
2019-06-22 21:51:07 +02:00
story := json.decode(Story, resp) or {
2019-06-23 10:41:42 +02:00
println('failed to decode a story')
exit(1)
2019-06-22 21:51:07 +02:00
}
f.mu.lock()
f.list_id++
cursor := f.list_id
f.mu.unlock()
println('#$cursor) $story.title | $story.url')
2019-06-22 21:51:07 +02:00
}
}
// Fetches top HN stories in 8 coroutines
fn main() {
2019-07-29 19:18:26 +02:00
resp := http.get('https://hacker-news.firebaseio.com/v0/topstories.json') or {
println('failed to fetch data from /v0/topstories.json')
return
}
2019-06-22 21:51:07 +02:00
ids := json.decode( []int, resp) or {
2019-07-29 19:18:26 +02:00
println('failed to decode topstories.json')
2019-06-22 21:51:07 +02:00
return
}
fetcher := &Fetcher{ids: ids}
for i := 0; i < NR_THREADS; i++ {
go fetcher.fetch()
}
time.sleep(5)
2019-06-22 21:51:07 +02:00
}