# 强制使用HTTP/1.1
curl -v --http1.1 https://example.com

# 强制使用HTTP/2
curl -v --http2 https://example.com

# 强制使用HTTP/3 (需要curl编译支持quic)
curl -v --http3 https://example.com

# 查看支持的HTTP版本
curl -v https://example.com 2>&1 | grep "SSL connection"

# 100 Continue场景
curl -v -X POST \
     -H "Expect: 100-continue" \
     -H "Content-Type: application/json" \
     -d '{"large":"data"}' \
     https://example.com/api

# 查看重定向链
curl -I -L https://example.com

# 输出示例
HTTP/1.1 301 Moved Permanently
Location: https://www.example.com
HTTP/2 301 
Location: https://example.com/
HTTP/2 200 OK

# 禁止跟随重定向
curl -I -I https://example.com  # -I 不跟随重定向

#!/bin/bash
# http_debug.sh - HTTP问题排查脚本

URL="${1:-https://example.com}"
METHOD="${2:-GET}"

echo "=== HTTP响应码排查 ==="
echo "URL: $URL"
echo "Method: $METHOD"
echo ""

# 获取响应头
echo "--- 响应头信息 ---"
curl -sI "$URL" | head -20

echo ""
echo "--- 完整响应（限前100行） ---"
curl -s -w "\n[HTTP状态码: %{http_code}]\n[响应时间: %{time_total}s]\n" \
     -o /tmp/response.txt "$URL"
head -100 /tmp/response.txt

echo ""
echo "--- 响应码分析 ---"
HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" "$URL")
case $HTTP_CODE in
    2*)
        echo "✅ 请求成功 (2xx)"
        ;;
    301|302|307|308)
        echo "⚠️ 重定向 - Location:"
        curl -sI "$URL" | grep -i location
        ;;
    400)
        echo "❌ 400 Bad Request - 检查请求参数"
        ;;
    401)
        echo "❌ 401 Unauthorized - Token过期或缺失"
        ;;
    403)
        echo "❌ 403 Forbidden - 权限不足"
        ;;
    404)
        echo "❌ 404 Not Found - 资源不存在"
        ;;
    429)
        echo "❌ 429 Too Many Requests - 请求被限流"
        ;;
    5*)
        echo "❌ 服务器错误 (5xx) - 查看服务端日志"
        ;;
    *)
        echo "❓ 未知响应码: $HTTP_CODE"
        ;;
esac

#!/bin/bash
# backend_check.sh - 后端服务健康检查

BACKEND_HOST="192.168.1.100"
BACKEND_PORT="8080"

echo "=== 后端服务健康检查 ==="
echo "目标: $BACKEND_HOST:$BACKEND_PORT"
echo ""

# 1. 检查端口监听
echo "--- 端口监听状态 ---"
ss -tlnp | grep ":$BACKEND_PORT"

# 2. 检查进程状态
echo ""
echo "--- 后端进程状态 ---"
ps aux | grep -E "java|node|python" | grep -v grep

# 3. 检查连接数
echo ""
echo "--- Nginx到后端连接数 ---"
ss -tnp | grep "$BACKEND_HOST:$BACKEND_PORT" | wc -l

# 4. 检查后端响应
echo ""
echo "--- 后端响应测试 ---"
curl -s -o /dev/null -w "响应码: %{http_code}\n响应时间: %{time_total}s\n" \
     --connect-timeout 3 \
     "http://$BACKEND_HOST:$BACKEND_PORT/health"

# 5. 查看nginx错误日志
echo ""
echo "--- Nginx 502/503/504错误日志 ---"
tail -20 /var/log/nginx/error.log | grep -E "502|503|504|upstream"

# 6. upstream配置检查
echo ""
echo "--- Nginx upstream配置 ---"
grep -A5 "upstream" /etc/nginx/conf.d/*.conf

# 查看X-Cache-Status
curl -I https://example.com/static/app.js

# 可能的值：
# MISS - 未命中缓存
# HIT - 命中缓存
# EXPIRED - 缓存过期
# STALE - 使用过期缓存（后端不可用）
# UPDATING - 正在更新缓存
# REVALIDATED - 已验证

# CDN响应头示例
HTTP/2 200
Server: nginx/1.20.1
Content-Type: application/javascript
Content-Length: 12345
Cache-Control: public, max-age=31536000
ETag: "abc123def456"
Last-Modified: Mon, 01 Jan 2024 00:00:00 GMT
Age: 3600  # 已被CDN缓存的时间
X-Cache: HIT from cdn.example.com

# 使用 ETag 验证
curl -I -H "If-None-Match: \"abc123\"" https://example.com/app.js
# 如果资源未变化，返回304 Not Modified

# 使用 Last-Modified 验证
curl -I -H "If-Modified-Since: Mon, 27 Apr 2026 00:00:00 GMT" https://example.com/app.js
# 如果资源未变化，返回304 Not Modified

#!/bin/bash
# cache_test.sh - 缓存测试脚本

URL="${1:-https://example.com}"

echo "=== 缓存测试 ==="
echo "URL: $URL"
echo ""

# 第一次请求
echo "--- 第一次请求 ---"
curl -sI "$URL" | grep -E "Cache-Control|ETag|Last-Modified|Expires|X-Cache"

echo ""
echo "--- 第二次请求（期望304或from cache） ---"
curl -sI "$URL" | grep -E "Cache-Control|ETag|Last-Modified|X-Cache"

# 获取ETag和Last-Modified
ETAG=$(curl -sI "$URL" | grep -i "etag" | cut -d' ' -f2 | tr -d '\r')
LAST_MODIFIED=$(curl -sI "$URL" | grep -i "last-modified" | cut -d' ' -f2- | tr -d '\r')

echo ""
echo "--- 使用ETag验证 ---"
if [[ -n "$ETAG" ]]; then
    curl -sI -H "If-None-Match: $ETAG" "$URL" | head -1
fi

echo ""
echo "--- 使用Last-Modified验证 ---"
if [[ -n "$LAST_MODIFIED" ]]; then
    curl -sI -H "If-Modified-Since: $LAST_MODIFIED" "$URL" | head -1
fi

#!/bin/bash
# http_troubleshoot.sh - HTTP问题排查脚本

URL="${1:-}"
METHOD="${2:-GET}"

if [[ -z "$URL" ]]; then
    echo "用法: $0 <URL> [METHOD]"
    echo "示例: $0 https://example.com/api GET"
    exit 1
fi

log() {
    echo "[$(date '+%H:%M:%S')] $1"
}

log "开始排查: $METHOD $URL"

# 1. DNS解析
log "DNS解析..."
dig +short $(echo $URL | sed 's|https\?://||' | cut -d/ -f1) | head -3

# 2. TCP连接
log "TCP连接..."
curl -s -o /dev/null -w "连接时间: %{time_connect}s\n" \
     --connect-timeout 5 "$URL"

# 3. TLS握手
log "TLS握手..."
curl -s -o /dev/null -w "TLS时间: %{time_appconnect}s\n" \
     --connect-timeout 5 "$URL"

# 4. 响应时间
log "总响应时间..."
curl -s -o /dev/null -w "总时间: %{time_total}s\n" \
     --connect-timeout 10 "$URL"

# 5. 响应码
log "HTTP响应码..."
HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" "$URL")
log "响应码: $HTTP_CODE"

# 6. 响应头
log "关键响应头..."
curl -sI "$URL" | grep -E "Server|X-Request-Id|Cache-Control|Content-Type"

# 7. 问题分析
log "问题分析..."
case $HTTP_CODE in
    000)
        log "❌ 连接失败 - 检查网络或服务状态"
        ;;
    200|201|204)
        log "✅ 请求成功"
        ;;
    301|302|307|308)
        log "⚠️ 重定向 - Location: $(curl -sI $URL | grep -i location | cut -d' ' -f2)"
        ;;
    400)
        log "❌ 400 Bad Request - 检查请求参数和格式"
        ;;
    401)
        log "❌ 401 Unauthorized - 检查认证信息"
        ;;
    403)
        log "❌ 403 Forbidden - 检查权限配置"
        ;;
    404)
        log "❌ 404 Not Found - 检查URL路径"
        ;;
    429)
        log "❌ 429 Too Many Requests - 请求被限流"
        ;;
    500)
        log "❌ 500 Internal Server Error - 查看服务端日志"
        ;;
    502)
        log "❌ 502 Bad Gateway - 检查upstream服务"
        ;;
    503)
        log "❌ 503 Service Unavailable - 服务可能过载"
        ;;
    504)
        log "❌ 504 Gateway Timeout - 检查upstream超时配置"
        ;;
    *)
        log "❓ 未知响应码"
        ;;
esac

# 检查缓存头
curl -I https://example.com/index.html
# Cache-Control: public, max-age=86400
# ETag: "v2"

# 手动清除缓存
curl -X PURGE https://example.com/index.html

# 强制刷新
curl -H "Cache-Control: no-cache" https://example.com/index.html

# 检查证书
openssl s_client -connect example.com:443 -servername example.com

# 检查证书过期
echo | openssl s_client -connect example.com:443 2>/dev/null | openssl x509 -noout -dates

# 检查证书链
openssl s_client -connect example.com:443 -showcerts

# 检查WebSocket握手
curl -I \
     -H "Connection: Upgrade" \
     -H "Upgrade: websocket" \
     -H "Sec-WebSocket-Version: 13" \
     -H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
     https://example.com/ws

# 期望响应
# HTTP/1.1 101 Switching Protocols
# Upgrade: websocket
# Connection: Upgrade