Line-Crawler
LINE Corporation •
Since 2015
Quick Actions
Official Docs
What is Line-Crawler?
Line-Crawler fetches web page content to generate link previews when URLs are shared in the LINE messaging app, which is widely popular in Japan, Taiwan, Thailand, and other Asian markets. The bot retrieves page titles, descriptions, and images to create rich link previews in chat conversations. It respects robots.txt directives.
User Agent String
Line/1.0 (compatible; Line-Crawler; +https://help.line.me/)
How to Control Line-Crawler
Block Completely
To prevent Line-Crawler from accessing your entire website, add this to your robots.txt file:
# Block Line-Crawler
User-agent: Line-Crawler
Disallow: /
Block Specific Directories
To restrict access to certain parts of your site while allowing others:
User-agent: Line-Crawler
Disallow: /admin/
Disallow: /private/
Disallow: /wp-admin/
Allow: /public/
Set Crawl Delay
To slow down the crawl rate (note: not all bots respect this directive):
User-agent: Line-Crawler
Crawl-delay: 10
How to Verify Line-Crawler
Verification Method:
Check user agent string for Line-Crawler identifier
Check user agent string for Line-Crawler identifier
Learn more in the official documentation.
Detection Patterns
Multiple ways to detect Line-Crawler in your application:
Basic Pattern
/Line\-Crawler/i
Strict Pattern
/^Line/1\.0 \(compatible; Line\-Crawler; \+https\://help\.line\.me/\)$/
Flexible Pattern
/Line\-Crawler[\s\/]?[\d\.]*?/i
Vendor Match
/.*LINE Corporation.*Line\-Crawler/i
Implementation Examples
// PHP Detection for Line-Crawler
function detect_line_crawler() {
$user_agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
$pattern = '/Line\\-Crawler/i';
if (preg_match($pattern, $user_agent)) {
// Log the detection
error_log('Line-Crawler detected from IP: ' . $_SERVER['REMOTE_ADDR']);
// Set cache headers
header('Cache-Control: public, max-age=3600');
header('X-Robots-Tag: noarchive');
// Optional: Serve cached version
if (file_exists('cache/' . md5($_SERVER['REQUEST_URI']) . '.html')) {
readfile('cache/' . md5($_SERVER['REQUEST_URI']) . '.html');
exit;
}
return true;
}
return false;
}
# Python/Flask Detection for Line-Crawler
import re
from flask import request, make_response
def detect_line_crawler():
user_agent = request.headers.get('User-Agent', '')
pattern = r'Line-Crawler'
if re.search(pattern, user_agent, re.IGNORECASE):
# Create response with caching
response = make_response()
response.headers['Cache-Control'] = 'public, max-age=3600'
response.headers['X-Robots-Tag'] = 'noarchive'
return True
return False
# Django Middleware
class LineCrawlerMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if self.detect_bot(request):
# Handle bot traffic
pass
return self.get_response(request)
// JavaScript/Node.js Detection for Line-Crawler
const express = require('express');
const app = express();
// Middleware to detect Line-Crawler
function detectLineCrawler(req, res, next) {
const userAgent = req.headers['user-agent'] || '';
const pattern = /Line-Crawler/i;
if (pattern.test(userAgent)) {
// Log bot detection
console.log('Line-Crawler detected from IP:', req.ip);
// Set cache headers
res.set({
'Cache-Control': 'public, max-age=3600',
'X-Robots-Tag': 'noarchive'
});
// Mark request as bot
req.isBot = true;
req.botName = 'Line-Crawler';
}
next();
}
app.use(detectLineCrawler);
# Apache .htaccess rules for Line-Crawler
# Block completely
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} Line\-Crawler [NC]
RewriteRule .* - [F,L]
# Or redirect to a static version
RewriteCond %{HTTP_USER_AGENT} Line\-Crawler [NC]
RewriteCond %{REQUEST_URI} !^/static/
RewriteRule ^(.*)$ /static/$1 [L]
# Or set environment variable for PHP
SetEnvIfNoCase User-Agent "Line\-Crawler" is_bot=1
# Add cache headers for this bot
<If "%{HTTP_USER_AGENT} =~ /Line\-Crawler/i">
Header set Cache-Control "public, max-age=3600"
Header set X-Robots-Tag "noarchive"
</If>
# Nginx configuration for Line-Crawler
# Map user agent to variable
map $http_user_agent $is_line_crawler {
default 0;
~*Line\-Crawler 1;
}
server {
# Block the bot completely
if ($is_line_crawler) {
return 403;
}
# Or serve cached content
location / {
if ($is_line_crawler) {
root /var/www/cached;
try_files $uri $uri.html $uri/index.html @backend;
}
try_files $uri @backend;
}
# Add headers for bot requests
location @backend {
if ($is_line_crawler) {
add_header Cache-Control "public, max-age=3600";
add_header X-Robots-Tag "noarchive";
}
proxy_pass http://backend;
}
}
Should You Block This Bot?
Recommendations based on your website type:
| Site Type | Recommendation | Reasoning |
|---|---|---|
| E-commerce | Optional | Evaluate based on bandwidth usage vs. benefits |
| Blog/News | Allow | Increases content reach and discoverability |
| SaaS Application | Block | No benefit for application interfaces; preserve resources |
| Documentation | Selective | Allow for public docs, block for internal docs |
| Corporate Site | Limit | Allow for public pages, block sensitive areas like intranets |
Advanced robots.txt Configurations
E-commerce Site Configuration
User-agent: Line-Crawler
Crawl-delay: 5
Disallow: /cart/
Disallow: /checkout/
Disallow: /my-account/
Disallow: /api/
Disallow: /*?sort=
Disallow: /*?filter=
Disallow: /*&page=
Allow: /products/
Allow: /categories/
Sitemap: https://example.com/sitemap.xml
Publishing/Blog Configuration
User-agent: Line-Crawler
Crawl-delay: 10
Disallow: /wp-admin/
Disallow: /drafts/
Disallow: /preview/
Disallow: /*?replytocom=
Allow: /
SaaS/Application Configuration
User-agent: Line-Crawler
Disallow: /app/
Disallow: /api/
Disallow: /dashboard/
Disallow: /settings/
Allow: /
Allow: /pricing/
Allow: /features/
Allow: /docs/
Quick Reference
User Agent Match
Line-Crawler
Robots.txt Name
Line-Crawler
Category
social
Respects robots.txt
Yes
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