pholcusvsgracy
Pholcus is a minimalistic web crawler library written in the Go programming language. It is designed to be flexible and easy to use, and it supports concurrent, distributed, and modular crawling.
Note that Pholcus is documented and maintained in the Chinese language and has no english resources other than the code source itself.
Gracy is an API client library based on httpx that provides an extra stability layer with:
- Retry logic
- Logging
- Connection throttling
- Tracking/Middleware
In web scraping, Gracy can be a convenient tool for creating scraper based API clients.
Example Use
package main
import (
"github.com/henrylee2cn/pholcus/exec"
_ "github.com/henrylee2cn/pholcus/spider/standard" // standard spider
)
func main() {
// create spider object
spider := exec.NewSpider(exec.NewTask("demo", "https://www.example.com"))
// add a callback for URL route by regex pattern. In this case it's any route:
spider.AddRule(".*", "Parse")
// Start spider
spider.Start()
}
// define callback here
func Parse(self *exec.Spider, doc *goquery.Document) {
// callbacks receive HTMl document reference and
}
# 0. Import
import asyncio
from typing import Awaitable
from gracy import BaseEndpoint, Gracy, GracyConfig, LogEvent, LogLevel
# 1. Define your endpoints
class PokeApiEndpoint(BaseEndpoint):
GET_POKEMON = "/pokemon/{NAME}" # 👈 Put placeholders as needed
# 2. Define your Graceful API
class GracefulPokeAPI(Gracy[str]):
class Config: # type: ignore
BASE_URL = "https://pokeapi.co/api/v2/" # 👈 Optional BASE_URL
# 👇 Define settings to apply for every request
SETTINGS = GracyConfig(
log_request=LogEvent(LogLevel.DEBUG),
log_response=LogEvent(LogLevel.INFO, "{URL} took {ELAPSED}"),
parser={
"default": lambda r: r.json()
}
)
async def get_pokemon(self, name: str) -> Awaitable[dict]:
return await self.get(PokeApiEndpoint.GET_POKEMON, {"NAME": name})
# Note: since Gracy is based on httpx we can customized the used client with custom headers etc"
def _create_client(self) -> httpx.AsyncClient:
client = super()._create_client()
client.headers = {"User-Agent": f"My Scraper"}
return client
pokeapi = GracefulPokeAPI()
async def main():
try:
pokemon = await pokeapi.get_pokemon("pikachu")
print(pokemon)
finally:
pokeapi.report_status("rich")
asyncio.run(main())