Annotation of libwww/Library/src/HTBind.html, revision 2.18
2.1 frystyk 1: <HTML>
2: <HEAD>
2.14 frystyk 3: <!-- Changed by: Henrik Frystyk Nielsen, 5-Jun-1996 -->
2.15 frystyk 4: <TITLE>W3C Sample Code Library libwww File Suffix Binding</TITLE>
2.1 frystyk 5: </HEAD>
6: <BODY>
2.12 frystyk 7: <H1>
8: File Suffix Binding Manager
9: </H1>
2.1 frystyk 10: <PRE>
11: /*
12: ** (c) COPYRIGHT MIT 1995.
13: ** Please first read the full copyright statement in the file COPYRIGH.
14: */
15: </PRE>
2.12 frystyk 16: <P>
2.18 ! frystyk 17: The preferences that we described in section
! 18: <A HREF="../User/Using/Prefs.html">Request Preferences</A> did not mention
! 19: what libwww should do if it doesn't know the data format of a document. In
! 20: many protocols this information is provided by the remote server. Typical
! 21: examples are MIME like protocols where the metainformation such as the
! 22: <EM>Content-Type</EM> and the <EM>Content-Language</EM> is provided together
! 23: with the document. However, applications often have access to the local file
! 24: system using <B>file</B> URLs which in general do not keep any or at least
! 25: very little information of the file type. It is therefore required to have
! 26: some kind of binding between the file system and the preferences registered
! 27: in the Library which provides this mateinformation about the object.
! 28: <P>
! 29: Often files in a file system is classified by some sort of a suffix, for
! 30: example, <TT>GIF</TT> files are often ending in <EM>.gif</EM>, text files
! 31: in <EM>.txt</EM> etc. This binding is not static and it is therefore required
! 32: to have a dynamic binding just like the preferences themselves. An example
! 33: of the latter is HTML files which on most Unix systems end in <EM>.html</EM>
! 34: whereas they on many MS-DOS based systems end in <EM>.htm</EM>.
! 35: <P>
! 36: This module provides a generic binding mechanism between a file and its
! 37: representation internally in libwww. It is not limited to simple file suffix
! 38: classification but can also be used in more advanced environments using data
! 39: bases etc. However, at this point we are interested in how we can register
! 40: bindings between file suffixes and for example content types, content languages
! 41: etc. The Bind manager is born with a certain knowledge about the set of
! 42: delimiters but more can be added to provide the functionality desired.
! 43: <P>
! 44: All the binding management could of course be replaced by a database interface.
2.12 frystyk 45: <P>
46: This module is implemented by <A HREF="HTBind.c">HTBind.c</A>, and it is
2.17 frystyk 47: a part of the <A HREF="http://www.w3.org/Library/"> W3C Sample Code
2.12 frystyk 48: Library</A>.
2.1 frystyk 49: <PRE>
50: #ifndef HTBIND_H
51: #define HTBIND_H
52:
53: #include "HTFormat.h"
54: #include "HTAnchor.h"
55: </PRE>
2.12 frystyk 56: <H2>
57: Initialization of the Module
58: </H2>
59: <P>
60: These functions must be called on startup and termination of the application.
61: This is done automatically by <A HREF="HTReq.html#Library">HTLibInit() and
62: HTLibTerminate()</A>.
2.1 frystyk 63: <PRE>
2.6 frystyk 64: extern BOOL HTBind_init (void);
65: extern BOOL HTBind_deleteAll (void);
2.1 frystyk 66: </PRE>
2.12 frystyk 67: <H2>
68: Case Sensitivity
69: </H2>
70: <P>
71: Should the search for suffixes be case sensitive or not? The default value
72: is <EM>case sensitive</EM>.
2.1 frystyk 73: <PRE>
2.6 frystyk 74: extern void HTBind_caseSensitive (BOOL sensitive);
2.1 frystyk 75: </PRE>
2.12 frystyk 76: <H2>
77: Suffix Delimiters
78: </H2>
79: <P>
80: Change the set of suffix delimiters. The default is a platform dependent
2.16 frystyk 81: set defined in the <A HREF="wwwsys.html">tcp module</A>.
2.1 frystyk 82: <PRE>
2.8 frystyk 83: extern const char *HTBind_delimiters (void);
84: extern void HTBind_setDelimiters (const char * new_suffixes);
2.1 frystyk 85: </PRE>
2.12 frystyk 86: <H2>
87: Set up Bindings Associated with a File Suffix
88: </H2>
89: <P>
2.10 frystyk 90: There are four types of bindings:
2.1 frystyk 91: <UL>
2.12 frystyk 92: <LI>
93: Content Type (media type)
94: <LI>
95: Language
96: <LI>
97: Content Encoding
98: <LI>
99: Content Transfer Encoding
2.1 frystyk 100: </UL>
2.12 frystyk 101: <P>
2.1 frystyk 102: And the associated set of methods is defined as:
103: <PRE>
2.8 frystyk 104: extern BOOL HTBind_add (const char * suffix,
105: const char * representation,
106: const char * encoding,
2.10 frystyk 107: const char * transfer,
2.8 frystyk 108: const char * language,
2.6 frystyk 109: double value);
110:
2.8 frystyk 111: extern BOOL HTBind_addType (const char * suffix,
112: const char * format,
2.6 frystyk 113: double value);
114:
2.8 frystyk 115: extern BOOL HTBind_addEncoding (const char * suffix,
116: const char * encoding,
2.6 frystyk 117: double value);
118:
2.10 frystyk 119: extern BOOL HTBind_addTransfer (const char * suffix,
120: const char * transfer,
121: double value);
122:
2.8 frystyk 123: extern BOOL HTBind_addLanguage (const char * suffix,
124: const char * language,
2.6 frystyk 125: double value);
2.1 frystyk 126: </PRE>
2.12 frystyk 127: <P>
128: The first method is a "super" method for binding information to a file suffic.
129: Any of the string values can be <CODE>NULL</CODE>. If filename suffix is
130: already defined its previous definition is overridden or modified. For example,
131: a <CODE>HTBind_setType</CODE> and <CODE>HTBind_setEncoding</CODE> can be
132: called with the same suffix.
133: <P>
134: Calling this with suffix set to "*" will set the default representation.
135: Calling this with suffix set to "*.*" will set the default representation
136: for unknown suffix files which contain a "."
137: <P>
138: <B>NOTE:</B> The suffixes <EM>can</EM> contain characters that must be escaped
139: in a URL. However, they should <EM>not</EM> be encoded when parsed as the
140: <CODE>suffix</CODE> parameter.
141: <H2>
142: Determine a suitable suffix
143: </H2>
144: <P>
145: Use the set of bindings to find a suitable suffix (or index) for a certain
146: combination of language, media type and encoding given in the anchor. Returns
147: a pointer to a suitable suffix string that must be freed by the caller. If
148: more than one suffix is found they are all concatenated. If no suffix is
149: found, NULL is returned.
2.1 frystyk 150: <PRE>
2.6 frystyk 151: extern char * HTBind_getSuffix (HTParentAnchor * anchor);
2.1 frystyk 152: </PRE>
2.12 frystyk 153: <H2>
154: Determine the content of an Anchor
155: </H2>
156: <P>
157: Use the set of bindings to find the combination of language, media type and
158: encoding of a given anchor. If more than one suffix is found they are all
159: searched. The last suffix has highest priority, the first one lowest. Returns
2.14 frystyk 160: the <A HREF="HTAnchor.html">HTAnchor object</A> with the representations
161: found. See also <CODE>HTBind_getFormat</CODE>
2.1 frystyk 162: <PRE>
2.14 frystyk 163: extern BOOL HTBind_getAnchorBindings (HTParentAnchor * anchor);
164: </PRE>
165: <H2>
166: Determine the content of a Response
167: </H2>
168: <P>
169: Use the set of bindings to find the combination of language, media type and
170: encoding of a given anchor. If more than one suffix is found they are all
171: searched. The last suffix has highest priority, the first one lowest. Returns
172: the <A HREF="HTResponse.html">HTResponse object</A> with the representations
173: found. See also <CODE>HTBind_getFormat</CODE>
174: <PRE>
175: extern BOOL HTBind_getResponseBindings (HTResponse * response,
176: const char * url);
2.1 frystyk 177: </PRE>
2.12 frystyk 178: <H2>
179: Determine the content of File
180: </H2>
181: <P>
182: Use the set of bindings to find the combination of language, media type and
183: encoding of a given anchor. If more than one suffix is found they are all
184: searched. The last suffix has highest priority, the first one lowest. Returns
185: the format, encoding, and language found. See also
2.1 frystyk 186: <CODE>HTBind_getBindings</CODE>.
187: <PRE>
2.10 frystyk 188: extern BOOL HTBind_getFormat (const char * filename,
189: HTFormat * format,
190: HTEncoding * enc,
2.11 frystyk 191: HTEncoding * cte,
2.10 frystyk 192: HTLanguage * lang,
193: double * quality);
2.1 frystyk 194: </PRE>
2.12 frystyk 195: <P>
2.1 frystyk 196: End of declaration module
197: <PRE>
198: #endif /* HTBIND_H */
199: </PRE>
2.12 frystyk 200: <P>
201: <HR>
2.10 frystyk 202: <ADDRESS>
2.18 ! frystyk 203: @(#) $Id: HTBind.html,v 2.17 1998/05/14 02:10:17 frystyk Exp $
2.10 frystyk 204: </ADDRESS>
2.12 frystyk 205: </BODY></HTML>
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