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1 | .\" -*-nroff-*- |
| 2 | .de VS |
| 3 | .sp 1 |
| 4 | .in +5n |
| 5 | .ft B |
| 6 | .nf |
| 7 | .. |
| 8 | .de VE |
| 9 | .ft R |
| 10 | .in -5n |
| 11 | .sp 1 |
| 12 | .fi |
| 13 | .. |
| 14 | .TH url 3mLib "20 June 1999" mLib |
| 15 | .SH NAME |
| 16 | url \- manipulation of form-urlencoded strings |
| 17 | .SH SYNOPSIS |
| 18 | .nf |
| 19 | .B "#include <mLib/url.h> |
| 20 | |
| 21 | .BI "void url_initenc(url_ectx *" ctx ); |
| 22 | .BI "void url_enc(url_ectx *" ctx ", dstr *" d , |
| 23 | .BI " const char *" name ", const char *" value ); |
| 24 | |
| 25 | .BI "void url_initdec(url_dctx *" ctx ", const char *" p ); |
| 26 | .BI "int url_dec(url_dctx *" ctx ", dstr *" n ", dstr *" v ); |
| 27 | .fi |
| 28 | .SH DESCRIPTION |
| 29 | The functions in |
| 30 | .B <mLib/url.h> |
| 31 | read and write `form-urlencoded' data, as specified in RFC1866. The |
| 32 | encoding represents a sequence of name/value pairs where both the name |
| 33 | and value are arbitrary binary strings (although the format is optimized |
| 34 | for textual data). An encoded string contains no nonprintable |
| 35 | characters or whitespace. This interface is capable of decoding any |
| 36 | urlencoded string; however, it can currently only |
| 37 | .I encode |
| 38 | names and values which do not contain null bytes, because the encoding |
| 39 | interface uses standard C strings. |
| 40 | .PP |
| 41 | Encoding a sequence of name/value pairs is achieved using the |
| 42 | .B url_enc |
| 43 | function. It requires as input an |
| 44 | .IR "encoding context" , |
| 45 | represented as an object of type |
| 46 | .BR url_ectx . |
| 47 | This must be initialized before use by passing it to the function |
| 48 | .BR url_initenc . |
| 49 | Each call to |
| 50 | .B url_enc |
| 51 | encodes one name/value pair, appending the encoded output to a dynamic |
| 52 | string (see |
| 53 | .BR dstr (3mLib) |
| 54 | for details). |
| 55 | .PP |
| 56 | Decoding a sequence of name/value pairs is performed using the |
| 57 | .B url_dec |
| 58 | function. It requires as input a |
| 59 | .IR "decoding context" , |
| 60 | represented as an object of type |
| 61 | .BR url_dctx . |
| 62 | This must be initialized before use by passing it to the function |
| 63 | .BR url_initdec , |
| 64 | along with the address of the urlencoded string to decode. The string |
| 65 | is not modified during decoding. Each call to |
| 66 | .B url_dec |
| 67 | extracts a name/value pair. The name and value are written to the |
| 68 | dynamic strings |
| 69 | .I n |
| 70 | and |
| 71 | .IR v , |
| 72 | so you probably want to reset them before each call. If there are no |
| 73 | more name/value pairs to read, |
| 74 | .B url_dec |
| 75 | returns zero; otherwise it returns a nonzero value. |
| 76 | .SH EXAMPLE |
| 77 | The example code below demonstrates converting between a symbol table |
| 78 | and a urlencoded representation. The code is untested. |
| 79 | .VS |
| 80 | #include <stdlib.h> |
| 81 | #include <mLib/alloc.h> |
| 82 | #include <mLib/dstr.h> |
| 83 | #include <mLib/sym.h> |
| 84 | #include <mLib/url.h> |
| 85 | |
| 86 | typedef struct { |
| 87 | sym_base _b; |
| 88 | char *v; |
| 89 | } val; |
| 90 | |
| 91 | void decode(sym_table *t, const char *p) |
| 92 | { |
| 93 | url_dctx c; |
| 94 | dstr n = DSTR_INIT, v = DSTR_INIT; |
| 95 | |
| 96 | for (url_initdec(&c, p); url_dec(&c, &n, &v); ) { |
| 97 | unsigned f; |
| 98 | val *vv = sym_find(t, n.buf, -1, sizeof(*vv), &f); |
| 99 | if (f) |
| 100 | free(vv->v); |
| 101 | vv->v = xstrdup(v.buf); |
| 102 | DRESET(&n); |
| 103 | DRESET(&v); |
| 104 | } |
| 105 | dstr_destroy(&n); |
| 106 | dstr_destroy(&v); |
| 107 | } |
| 108 | |
| 109 | void encode(sym_table *t, dstr *d) |
| 110 | { |
| 111 | sym_iter i; |
| 112 | url_ectx c; |
| 113 | val *v; |
| 114 | |
| 115 | url_initenc(&c); |
| 116 | for (sym_mkiter(&i, t); (v = sym_next(&i)) != 0; ) |
| 117 | url_enc(&c, d, SYM_NAME(v), v->v); |
| 118 | } |
| 119 | .VE |
| 120 | .SH AUTHOR |
| 121 | Mark Wooding, <mdw@nsict.org>. |
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