seenreq
A library to test if a url/request is crawled, usually used in a web crawler. Compatible with request and node-crawler. The 1.x or newer version has quite different APIs and is not compatible with 0.x versions. Please read the upgrade guide document.
Table of Contents
Quick Start
Installation
$ npm install seenreq --save
Basic Usage
const seenreq = require('seenreq')
, seen = new seenreq();
let url = "http://www.GOOGLE.com";
console.log(seen.normalize(url));
let option = {
uri: 'http://www.GOOGLE.com',
rupdate: false
};
console.log(seen.normalize(option));
seen.initialize().then(()=>{
return seen.exists(url);
}).then( (rst) => {
console.log(rst[0]);
return seen.exists(opt);
}).then( (rst) => {
console.log(rst[0]);
}).catch(e){
console.error(e);
};
When you call exists
, the module will do normalization itself first and then check if exists.
Use Redis
seenreq
stores keys in memory by default, memory usage will soar as number of keys increases. Redis will solve this problem. Because seenreq uses ioredis
as redis client, all ioredis
' options are recived and supported. You should first install:
npm install seenreq-repo-redis --save
and then set repo to redis
:
const seenreq = require('seenreq')
let seen = new seenreq({
repo:'redis',
host:'127.0.0.1',
port:6379,
clearOnQuit:false
});
seen.initialize().then(()=>{
}).catch(e){
console.error(e);
}
Use mongodb
It is similar with redis above:
npm install seenreq-repo-mongo --save
const seenreq = require('seenreq')
let seen = new seenreq({
repo:'mongo',
url:'mongodb://xxx/seenreq',
collection: 'foor'
});
Class:seenreq
Instance of seenreq
seen.initialize()
Initialize the repo, returns a promise.
seen.normalize(uri|option[,options])
Returns normalized Object: {sign,options}.
seen.exists(uri|option|array[,options])
Returns a promise with an Boolean array, e.g. [true, false, true, false, false].
seen.dispose()
Dispose resources of repo. If you are using repo other than memory, like Redis you should call dispose
to release connection. Returns a promise.
Options
- removeKeys: Array, Ignore specified keys when doing normalization. For instance, there is a
ts
property in the url like http://www.xxx.com/index?ts=1442382602504
which is timestamp and it should be same whenever you visit. - stripFragment: Boolean, Remove the fragment at the end of the URL (Default true).
- rupdate: Boolean, it is short for
repo update
. Store in repo so that seenreq
can hit the same req
next time (Default true).
RoadMap
- add
mysql
repo to persist keys to disk. - add keys life time management.