教你使用Apache搭建Http下載伺服器

2022-11-01 14:03:49

前言

前段時間因為某些原因，幾大主流網路硬碟都無法使用，正好手頭上有臺閒置的雲伺服器，於是就想來搭建一個檔案下載服務，使用者只需通過一個連結就能下載軟體。

Apache快速上手

經過調研，發現Ubuntu採用Apache2這個軟體就可以快速滿足我的需求。

安裝Apache2

apt-get install apache2

安裝好之後，啟動Apache2服務：

/etc/init.d/apache2 start

檢視啟動狀態：

/etc/init.d/apache2 status

然後，存取伺服器的公網ip或域名，就可以看到如下介面，此時說明Apache正常工作：

最後在/var/www/html路徑下，刪除index.html，上傳自己想要被下載的檔案，再次存取，就可以進行下載了。
(注：如果是雲伺服器，還需要在安全組開放80和443埠號)
同時，也可以通過域名/檔名的方式直接給別人一個連結，進行下載。

如果有一臺單獨的伺服器用於臨時檔案的分享，這樣很快就搞定了。
下面來繼續進行深入研究，考慮更現實的場景。

修改埠號

Apache2預設採用的是80埠號，因此直接通過公網ip或域名就能存取。現實中，很多伺服器本身就部署了許多其它服務，80埠號往往被佔用，因此就需要將Apache2改成其它存取埠。

修改埠，首先需要修改/etc/apache2/ports.conf這個檔案：
這裡吧80改成其它不衝突的埠號，我這裡以1024為例

#Listen 80
Listen 1024
<IfModule ssl_module>
        Listen 443
</IfModule>
<IfModule mod_gnutls.c>
        Listen 443
</IfModule>

然後修改/etc/apache2/sites-available/000-default.conf

#<VirtualHost *:80>
<VirtualHost *:1024>
        # The ServerName directive sets the request scheme, hostname and port that
        # the server uses to identify itself. This is used when creating

注：這個檔案中還有一個DocumentRoot，修改該引數可以調整檔案系統的根路徑。

修改完成之後，重啟apache2：

/etc/init.d/apache2 restart

此時，就可以通過存取域名:1024的形式存取到同樣內容，例如我的伺服器存取url為http://xdxsb.top:1024

設定存取限制

個人伺服器很容易遭到別人的攻擊，如果有人開好多執行緒來反覆請求下載，這就將導致流量頻寬消耗巨大，甚至會讓伺服器宕機。因此，長期提供下載服務的伺服器必須設定存取限制。

組態檔引數詳解

存取限制主要涉及到/etc/apache2/apache2.conf這個組態檔，首先來對該檔案進行解讀。
這個檔案內容如下：

# This is the main Apache server configuration file. It contains the
# configuration directives that give the server its instructions.
# See http://httpd.apache.org/docs/2.4/ for detailed information about
# the directives and /usr/share/doc/apache2/README.Debian about Debian specific
# hints.
#
#
# Summary of how the Apache 2 configuration works in Debian:
# The Apache 2 web server configuration in Debian is quite different to
# upstream's suggested way to configure the web server. This is because Debian's
# default Apache2 installation attempts to make adding and removing modules,
# virtual hosts, and extra configuration directives as flexible as possible, in
# order to make automating the changes and administering the server as easy as
# possible.
# It is split into several files forming the configuration hierarchy outlined
# below, all located in the /etc/apache2/ directory:
#
#   /etc/apache2/
#   |-- apache2.conf
#   |   `-- ports.conf
#   |-- mods-enabled
#   |   |-- *.load
#   |   `-- *.conf
#   |-- conf-enabled
#   |   `-- *.conf
#    `-- sites-enabled
#      `-- *.conf
#
#
# * apache2.conf is the main configuration file (this file). It puts the pieces
# together by including all remaining configuration files when starting up the
# web server.
#
# * ports.conf is always included from the main configuration file. It is
# supposed to determine listening ports for incoming connections which can be
# customized anytime.
#
# * Configuration files in the mods-enabled/, conf-enabled/ and sites-enabled/
# directories contain particular configuration snippets which manage modules,
# global configuration fragments, or virtual host configurations,
# respectively.
#
# They are activated by symlinking available configuration files from their
# respective *-available/ counterparts. These should be managed by using our
# helpers a2enmod/a2dismod, a2ensite/a2dissite and a2enconf/a2disconf. See
# their respective man pages for detailed information.
#
# * The binary is called apache2. Due to the use of environment variables, in
# the default configuration, apache2 needs to be started/stopped with
# /etc/init.d/apache2 or apache2ctl. Calling /usr/bin/apache2 directly will not
# work with the default configuration.
# Global configuration
#
#
# ServerRoot: The top of the directory tree under which the server's
# configuration, error, and log files are kept.
#
# NOTE! If you intend to place this on an NFS (or otherwise network)
# mounted filesystem then please read the Mutex documentation (available
# at <URL:http://httpd.apache.org/docs/2.4/mod/core.html#mutex>);
# you will save yourself a lot of trouble.
#
# Do NOT add a slash at the end of the directory path.
#
#ServerRoot "/etc/apache2"
#
# The accept serialization lock file MUST BE STORED ON A LOCAL DISK.
#
#Mutex file:${APACHE_LOCK_DIR} default
#
# The directory where shm and other runtime files will be stored.
#
DefaultRuntimeDir ${APACHE_RUN_DIR}
#
# PidFile: The file in which the server should record its process
# identification number when it starts.
# This needs to be set in /etc/apache2/envvars
#
PidFile ${APACHE_PID_FILE}
#
# Timeout: The number of seconds before receives and sends time out.
#
Timeout 300
#
# KeepAlive: Whether or not to allow persistent connections (more than
# one request per connection). Set to "Off" to deactivate.
#
KeepAlive On
#
# MaxKeepAliveRequests: The maximum number of requests to allow
# during a persistent connection. Set to 0 to allow an unlimited amount.
# We recommend you leave this number high, for maximum performance.
#
MaxKeepAliveRequests 100
#
# KeepAliveTimeout: Number of seconds to wait for the next request from the
# same client on the same connection.
#
KeepAliveTimeout 5
# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}
#
# HostnameLookups: Log the names of clients or just their IP addresses
# e.g., www.apache.org (on) or 204.62.129.132 (off).
# The default is off because it'd be overall better for the net if people
# had to knowingly turn this feature on, since enabling it means that
# each client request will result in AT LEAST one lookup request to the
# nameserver.
#
HostnameLookups Off
# ErrorLog: The location of the error log file.
# If you do not specify an ErrorLog directive within a <VirtualHost>
# container, error messages relating to that virtual host will be
# logged here. If you *do* define an error logfile for a <VirtualHost>
# container, that host's errors will be logged there and not here.
#
ErrorLog ${APACHE_LOG_DIR}/error.log
#
# LogLevel: Control the severity of messages logged to the error_log.
# Available values: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the log level for particular modules, e.g.
# "LogLevel info ssl:warn"
#
LogLevel warn
# Include module configuration:
IncludeOptional mods-enabled/*.load
IncludeOptional mods-enabled/*.conf
# Include list of ports to listen on
Include ports.conf
# Sets the default security model of the Apache2 HTTPD server. It does
# not allow access to the root filesystem outside of /usr/share and /var/www.
# The former is used by web applications packaged in Debian,
# the latter may be used for local directories served by the web server. If
# your system is serving content from a sub-directory in /srv you must allow
# access here, or in any related virtual host.
<Directory />
   Options FollowSymLinks
   AllowOverride None
   Require all denied
</Directory>
<Directory /usr/share>
   AllowOverride None
   Require all granted
</Directory>
<Directory /var/www/>
   Options Indexes FollowSymLinks
   AllowOverride None
   Require all granted
</Directory>
#<Directory /srv/>
#   Options Indexes FollowSymLinks
#   AllowOverride None
#   Require all granted
#</Directory>
# AccessFileName: The name of the file to look for in each directory
# for additional configuration directives. See also the AllowOverride
# directive.
#
AccessFileName .htaccess
#
# The following lines prevent .htaccess and .htpasswd files from being
# viewed by Web clients.
#
<FilesMatch "^.ht">
   Require all denied
</FilesMatch>
#
# The following directives define some format nicknames for use with
# a CustomLog directive.
#
# These deviate from the Common Log Format definitions in that they use %O
# (the actual bytes sent including headers) instead of %b (the size of the
# requested file), because the latter makes it impossible to detect partial
# requests.
#
# Note that the use of %{X-Forwarded-For}i instead of %h is not recommended.
# Use mod_remoteip instead.
#
LogFormat "%v:%p %h %l %u %t "%r" %>s %O "%{Referer}i" "%{User-Agent}i"" vhost_combined
LogFormat "%h %l %u %t "%r" %>s %O "%{Referer}i" "%{User-Agent}i"" combined
LogFormat "%h %l %u %t "%r" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
# Include of directories ignores editors' and dpkg's backup files,
# see README.Debian for details.
# Include generic snippets of statements
IncludeOptional conf-enabled/*.conf
# Include the virtual host configurations:
IncludeOptional sites-enabled/*.conf
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

引數解釋：

PidFile:記錄伺服器啟動程序號的檔案
Timeout:接收和傳送前超時秒數
KeepAlive:是否允許穩固的連線(每個連線有多個請求)，設為"Off"則停用
MaxKeepAliveRequests:在穩固連線期間允許的最大請求數，設為0表示無限制接入
KeepAliveTimeout:在同一個連線上從同一臺客戶上接收請求的秒數
User/Group:執行的使用者和組
HostnameLookups：指定記錄使用者端的名字還是IP地址
例如，本指令為on時記錄主機名，如www.apache.org；為off時記錄IP地址，204.62.129.132。預設值為off，這要比設為on好得多，因為如果設為on則每個使用者端請求都將會至少造成對 nameserver 進行一次查詢。
ErrorLog:錯誤紀錄檔檔案定位
LogLevel:控制記錄在錯誤紀錄檔檔案中的紀錄檔資訊
可選值：debug，info，notice，warn，error，crit，alert，emerg
Directory：在標籤對裡面可以設定各資料夾屬性
- Options：控制在特定目錄中將使用哪些伺服器特性
  - All：除MultiViews之外的所有特性，這是預設設定
  - ExecCG：允許使用mod_cgi執行CGI指令碼
  - FollowSymLinks：伺服器允許在此目錄中使用符號連線，如果此設定位於設定段中，則會被忽略
  - Includes：允許使用mod_include提供的伺服器端包含
  - IncludesNOEXEC：允許伺服器端包含，但禁用"#exec cmd"和"#exec cgi"，但仍可以從ScriptAlias目錄使用"#include virtual"虛擬CGI指令碼
  - Indexes：如果一個對映到目錄的URL被請求，而此目錄中又沒有DirectoryIndex(例如：index.html)，那麼伺服器會返回由mod_autoindex生成的一個格式化後的目錄列表
  - MultiViews：允許使用mod_negotiation提供內容協商的"多重檢視"(MultiViews)
  - SymLinksIfOwnerMatch：伺服器僅在符號連線與其目的目錄或檔案的擁有者具有相同的uid時才使用它。如果此設定出現在設定段中，則將被忽略
- AllowOverride：確定允許存在於.htaccess檔案中的指令型別
  語法：AllowOverride All|None|directive-type [directive-type]
  如果此指令被設定為None ，那麼.htaccess檔案將被完全忽略。
  directive-type可以是下列各組指令之一：
  - AuthConfig : 允許使用與認證授權相關的指令
  - FileInfo : 允許使用控制檔案型別的指令、控制檔案後設資料的指令、mod_rewrite中的指令、mod_actions中的Action指令
  - Indexes : 允許使用控制目錄索引的指令
  - Limit : 允許使用控制主機存取的指令
- Order：控制預設的存取狀態與Allow和Deny指令生效的順序
  - Deny,Allow : Deny指令在Allow指令之前被評估。預設允許所有存取。任何不匹配Deny指令或者匹配Allow指令的客戶都被允許存取
  - Allow,Deny : Allow指令在Deny指令之前被評估。預設拒絕所有存取。任何不匹配Allow指令或者匹配Deny指令的客戶都將被禁止存取
  - Mutual-failure : 只有出現在Allow列表並且不出現在Deny列表中的主機才被允許存取。這種順序與"Order Allow,Deny"具有同樣效果
- Allow：控制哪些主機可以存取伺服器的該區域。可以根據主機名、IP地址、 IP地址範圍或其他環境變數中捕獲的使用者端請求特性進行控制。
  語法：Allow from all|host|env=env-variable [host|env=env-variable]
- Deny：控制哪些主機被禁止存取伺服器的該區域。可以根據主機名、IP地址、 IP地址範圍或其他環境變數中捕獲的使用者端請求特性進行控制。
  語法：Deny from all|host|env=env-variable [host|env=env-variable]
- Require：存取限制
  - all granted：表示允許所有主機存取
  - all denied：表示拒絕所有主機存取
  - local：表示僅允許本地主機存取
  - [not] host <主機名或域名列表>：表示允許或拒絕指定主機或域名存取
  - [not] ip <IP地址或網段列表>：表示允許或拒絕指定的IP地址或網段存取
AccessFileName：設定分散式組態檔的名字，預設為.htaccess
如果為某個目錄啟用了分散式組態檔功能，那麼在向用戶端返回其中的檔案時，伺服器將在這個檔案所在的各級目錄中查詢此組態檔
<FilesMatch"^.ht">：拒絕對.ht開標頭檔案的存取,以保護.htaccess檔案
LogFormat：定義存取紀錄檔的格式

限制連線量

通過上面對組態檔引數的研究，注意到MaxKeepAliveRequests這個引數限制了對於單個連線最大的存取量為100，因此無需擔心單執行緒指令碼反覆頻繁請求的問題。
那麼對於高並行的請求，Apache是否有預設設定的策略呢？也是有的，從2.0開始，apache引入了MPM（Multi-Processing Module，多程序處理模組），MPM有prefork, worker和event這三種模式[4]，可以通過下面的命令檢視當前apache所採用的模式：

apachectl -V | grep -i mpm

預設採用的應該是event模式。

這個模式的組態檔位於/etc/apache2/mods-availablempm_event.conf
預設引數：

<IfModule mpm_event_module>
        StartServers             2
        MinSpareThreads          25
        MaxSpareThreads          75
        ThreadLimit              64
        ThreadsPerChild          25
        MaxRequestWorkers        150
        MaxConnectionsPerChild   0
</IfModule>

引數解釋：

StartServers：啟動時程序數
MinSpareThreads：最小空閒執行緒數
MaxSpareThreads：最大空閒執行緒數
ThreadLimit：每個程序可以啟動的執行緒數量上限值
ThreadsPerChild：每個程序可以啟動的執行緒數量
MaxRequestWorkers：執行緒數量最大值
MaxConnectionsPerChild：最大連線數限制

我這裡沒去調整，先用JMeter來進行一個多執行緒並行測試：
JMeter下載地址：https://jmeter.apache.org/download_jmeter.cgi

解壓之後，執行apache-jmeter-5.5/bin/jmeter.bat，即可啟動。

建立一個執行緒組，我這設定了1000個執行緒數，時間設為0.01秒

再設定HTTP請求，填寫請求域名，埠號，檔案路徑

測試結果顯示，請求失敗率為16%，因此我這小破伺服器，基本上1000個並行請求都難以滿足。

封禁ip

如果面對惡意攻擊，那最快解決問題的辦法無疑是封禁它的ip，這裡嘗試一下封禁本機ip，看看是否有效。

首先查詢本機ip，直接在百度搜尋ip，即可查詢到公網ip，注意這裡一定要是公網ip，通過ipconfig查詢出的是內網ip。

修改組態檔：

vim /etc/apache2/apache2.conf

修改/var/www/檔案內容：

<Directory /var/www/>
        Options Indexes FollowSymLinks
        AllowOverride None
        <RequireAll>
                Require all granted
                Require not ip 111.11.81.152
        </RequireAll>
</Directory>

重啟服務：

 /etc/init.d/apache2 restart

再次存取，發現許可權受限，說明設定成功。

拓展：如果只允許某個固定ip存取，那麼可以這樣修改：

<Directory /var/www/>
        Options Indexes FollowSymLinks
        AllowOverride None
        # Require all granted
        Require ip 111.11.82.8
</Directory>

設定賬號密碼存取

對於某些私密檔案，可以進一步設定賬號密碼進行身份驗證。

首先建立一個資料夾用來儲存使用者資訊：

mkdir -p /usr/local/conf

然後建立使用者：

htpasswd -c /usr/local/conf/.usr zstar

zstar是我建立的使用者名稱

輸入密碼後，Apache會以密文方式儲存密碼，可以通過下面的方式檢視使用者名稱和密碼密文：

cat /usr/local/conf/.usr

再次修改組態檔：

vim /etc/apache2/apache2.conf

修改內容：

<Directory /var/www/>
        Options Indexes FollowSymLinks
        AllowOverride All
        AuthName "apache"
        AuthType Basic
        AuthUserFile "/usr/local/conf/.usr"
        Require user zstar
</Directory>

重啟服務：