Web Server v4.03

This is my rudimentary HTTP server, written in Java. While it will never compare to something like Apache, JWS or IIS, it has the advantage that it's free, easy to install and easy to configure. Historically, I wrote this program simply to serve files over HTTP (I needed something to transfer a file...don't ask); later I added directory browsing, and most recently added CGI support.

Among the more prominent features: Prior to the major rewrite in June of 1999, the web server created a new thread to handle each connection. However, this method is very inefficient; because creating threads is a rather expensive operation (at least on Windows), I reworked the program to create a pool of request handling threads; now the threads could be recycled. This lead to a dramatic increase in performance, as I no longer had thread-creation latencies.

The next feature I added was virtual hosting support, a la Apache. Under the new program design, the life of a request handler involved many modifications to the handler's request data. Therefore, the logical progression was to create virtual hosts and serve data differently depending on the value of the Host: header.

The last major modification of the code came in July of 1999; I reworked the request handler to delegate the handling of different types of HTTP commands to different classes, thereby separating common HTTP functions from functions that are specific to, say, GET and HEAD commands. It also allowed me to easily integrate CGI support.

To run this program, type java httpd -c configfile. Unlike previous versions, all options must be placed in a configuration file.

Configuration files are meant to resemble Java source code...but I don't implement every single detail of the syntax. A sample configuration file is below:

01: // thibs.cfg -- configuration file for thibs
02: // Copyright (C) 1999 Darrick Wong
04: httpdconf {
05:	 DebugLevel=-1;
06:	 NormalLogFile=thibs.log;
07:	 ErrorLogFile=thibs.log;
08: }
10: VHostConf {
11:	 WebAdminEmail=dork@thibs.menloschool.org;
12:	 DocumentRoot=/home/djwong/public_html/;
13:	 CgiRoot=/home/djwong/public_html/;
14:	 HostName=djwong;
15: }
17: VHostConf {
18:	 WebAdminEmail=dork@thibs.menloschool.org;
19:	 DocumentRoot=/home/djwong/public_html/kubiak/;
20:	 HostName=kubiak;
21: }
23: VHostConf {
24:	 WebAdminEmail=dork@thibs.menloschool.org;
25:	 DocumentRoot=/home/sweaglesw/public_html/whale/;
26:	 CgiRoot=/home/sweaglesw/public_html/random/;
27:	 HostName=whale;
28: }
30: VHostConf {
31:	 WebAdminEmail=dork@thibs.menloschool.org;
32:	 DocumentRoot=/;
33:	 HostName=default;
34: }
36: ServerConf {
37:	 Port=2000;
38:	 DebugLevel=9;
39:	 SysAdminEmail=dork@thibs.menloschool.org;
40:	 VirtualHosts=default,djwong,kubiak;
41: }
43: ServerConf {
44:	 Port=80;
45:	 DebugLevel=9;
46:	 SysAdminEmail=dork@thibs.menloschool.org;
47:	 VirtualHosts=default,kubiak,whale;
48: }

Let's dissect this configuration file step by step. The first two lines are comments describing the configuration file. To initialize the web server, we must first create a configuration object for the entire HTTP server as a whole. Therefore, in line 4, we create a httpdconf "object" and set some of its properties. Here, we set the debug level to -1, indicating that we don't want any error messages. Then, we set up log files for standard error and standard output. To see a table of possible properties for httpdconf, follow this link.

Next, we must create virtual hosts. To do so, we create a bunch of VHostConf objects and set their properties. Every virtual host must have a name; if none is provided, then "default" becomes the host name. No two virtual hosts can have the same name; if you try, then the server will complain. In the first virtual host configuration objec,t we set the webmaster's email address for that host, we specify a document root and finally a root for CGI support. The others are very similar, only they have slightly different parameters. To see a table of possible properties for VHostConf, follow this link.

Finally, we must create servers to listen on different ports. For that, we use the ServerConf object. You can create as many ServerConf objects as you like. Here, we create two servers. The first one runs on port 2000. Notice the line that starts with VirtualHosts. This line lists the virtual hosts associated with that particular server; host names are separated with commas. Hosts can be associated with multiple servers; note that the first entry specifies the virtual host that is used if the Host: header is invalid or nonexistant. For a list of possible properties for ServerConf objects, follow this link.

Options for httpdconf

Property Name Description
DebugLevel Debugging level. Varying numbers of debug messages appear based on this value; if you specify -1, then nothing appears; if you specify 9, then everything appears. Default: -1.
NormalLogFile Standard output is redirected to this file. Default: no redirection.
ErrorLogFile Standard output is redirected to this file. Default: no redirection.

Options for VHostConf

Property Name Description
BufferSize Memory buffer size for file transfer. Default: 131072 bytes.
ShowIcons Toggles the showing of icons in directory listings. Default: true.
ListFolderUsingTables Toggles the use of tables in directory listings. Tables result in a cleaner appearance but increase the amount of data that must be sent. Default: true.
ListFolders Toggles directory browsing. If you disable this option, then users get a 403 error if there is no default file. Default: true.
LookForDefaultFiles Toggles the searching for default files in a folder. If you have this option enabled, then the web server will look for files to send to the browser when the user references a directory. If this option is disabled, then the user gets a directory listing. If directory listings are disabled, then the user gets a 403 error. Default: true.
BrowserCachingEnabled Toggles the use of the Last-Modified HTTP header. If that header is not sent, then browsers will generally not cache anything sent by the web server and will therefore have to re-query the server. Disabling this option is not recommended because it is counter HTTP 1.1 policies and increases network traffic and server load. Default: true.
FileSystemCaseSensitive Toggles whether or not to pay attention to the case of file names when sorting names. If disabled, AUTOEXEC.BAT is the same as autoexec.bat. Default: false.
UseJavaScriptInTableListings Toggles the use of JavaScript in table listings. If enabled, then the standard folder selector at the top is replaced by a drop-down list (if the drop-down list is enabled), and table headings (if tables in directory listings are enabled) become a bit more interactive. Default: true.
UseComboBoxForDirectoryNavigation Toggles the use of a drop-down list for directory navigation. You must have JavaScript in folder listings enabled. Default: true.
CGITimeoutAfterDeathTimeout Amount of time, in milliseconds, that the web server continues to send output to the client after termination of the CGI. Default: 1000ms.
VFSRoot The folder containing the Virtual File System files. These files are used for serving images and stylesheets for directory listings, and is also used as a hack to test error handling code and get server status information. Default: "./VFS/".
WebAdminEmail The e-mail address of the administrator for this virtual host. Default: webmaster@localhost.
DocumentRoot The folder containing the files that you want to serve over HTTP. This is equivalent of \inetpub\wwwroot in IIS, and htdocs in Apache. Default: "./htdocs/".
CGIRoot The folder containing CGI scripts. Any files referenced here (through the virtual folder cgi-bin) are executed, rather than simply copied. Default: "./VFS/".
HostName This is the name of this virtual host. When accepting a connection, the request handler reads the Host header, if any, and tries to match it with a VHostConf object. If it doesn't find one, then it uses the first VHostConf for configuration data. This value MUST be provided; there is no default.
DefaultFiles A comma separated list of files to look for when a URI refers to a folder. The files are search for as they are listed in this line; the first file in the list is looked for first. Default: index.html,index.htm,default.html,default.htm.
MimeDatabase This is the name of a file containing MIME file type information. The format of this file should be extension =mimetype; the extension should NOT have a leading period. The default for this setting is "./mimetype.txt"; please change this setting so that the path settings are correct.

Options for ServerConf

Property Name Description
Port The port that this particular server listens to. Default: 80.
DebugLevel Debugging level. Varying numbers of debug messages appear based on this value; if you specify -1, then nothing appears; if you specify 9, then everything appears. Default: -1.
SysAdminEmail The e-mail address of the system administrator. Default: root@localhost.
TimeoutMillis If the client does not send data for the specified length of time (in milliseconds), the server disconnects the connection. Default: 30000ms (30 seconds)
VirtualHosts This is a comma-separated list of virtual hosts that are associated with this server. The first host in this lists is used as the default host if the client does not specify a Host header or the value of the Host does not match any other host name.

Download the entire package.

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