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| author | Mark Pulford <mark@kyne.com.au> | 2011-12-12 23:23:32 +1030 |
|---|---|---|
| committer | Mark Pulford <mark@kyne.com.au> | 2011-12-12 23:23:32 +1030 |
| commit | 71c5dd86f14a73d97e2cb57e81755c4844938697 (patch) | |
| tree | 124d6c7a1d46463826cd9d45e288f200b7b05e08 /README | |
| parent | bd994cd7976ac93c530792e3c0d6f45a33c757b4 (diff) | |
| download | lua-cjson-71c5dd86f14a73d97e2cb57e81755c4844938697.tar.gz lua-cjson-71c5dd86f14a73d97e2cb57e81755c4844938697.tar.bz2 lua-cjson-71c5dd86f14a73d97e2cb57e81755c4844938697.zip | |
Convert documentation to AsciiDoc
- Rename README to manual.txt and add AsciiDoc markup
- Rewrite some sections of documentation (more outstanding)
- Add "doc" Makefile target
- Update RPM spec file to include HTML output
Diffstat (limited to 'README')
| -rw-r--r-- | README | 328 |
1 files changed, 0 insertions, 328 deletions
| @@ -1,328 +0,0 @@ | |||
| 1 | Lua CJSON v1.0.4 | ||
| 2 | ================ | ||
| 3 | |||
| 4 | Lua CJSON is covered by the MIT license. See the file "LICENSE" for | ||
| 5 | details. | ||
| 6 | |||
| 7 | Lua CJSON provides fast JSON parsing and encoding support for Lua. | ||
| 8 | |||
| 9 | Features: | ||
| 10 | - 10x to 20x quicker (or more) than the fastest pure Lua JSON modules. | ||
| 11 | - Full support for JSON with UTF-8, including decoding surrogate | ||
| 12 | pairs. | ||
| 13 | - Optional run-time support for common exceptions to the JSON | ||
| 14 | specification (NaN, Inf,..). | ||
| 15 | |||
| 16 | Caveats: | ||
| 17 | - UTF-16 and UTF-32 are not supported. | ||
| 18 | - Multi-threading within a single Lua state is not supported. | ||
| 19 | However, this is not a recommended configuration under Lua. | ||
| 20 | |||
| 21 | To obtain the latest version of Lua CJSON visit: | ||
| 22 | |||
| 23 | http://www.kyne.com.au/~mark/software/lua-cjson.php | ||
| 24 | |||
| 25 | Feel free to email me if you have any patches, suggestions, or | ||
| 26 | comments. | ||
| 27 | |||
| 28 | - Mark Pulford <mark@kyne.com.au> | ||
| 29 | |||
| 30 | |||
| 31 | Installing | ||
| 32 | ========== | ||
| 33 | |||
| 34 | Build requirements: | ||
| 35 | - Lua (http://www.lua.org/) | ||
| 36 | Or: | ||
| 37 | - LuaJIT (http://www.luajit.org/) | ||
| 38 | |||
| 39 | There are 3 build methods available: | ||
| 40 | - Make: POSIX, OSX | ||
| 41 | - RPM: Various Linux distributions | ||
| 42 | - LuaRocks (http://www.luarocks.org/): POSIX, OSX, Windows | ||
| 43 | |||
| 44 | |||
| 45 | Make | ||
| 46 | ---- | ||
| 47 | |||
| 48 | Review and update the included Makefile to suit your platform. Next, | ||
| 49 | build and install the module: | ||
| 50 | |||
| 51 | # make | ||
| 52 | # make install | ||
| 53 | OR | ||
| 54 | # cp cjson.so [your_module_directory] | ||
| 55 | |||
| 56 | |||
| 57 | RPM | ||
| 58 | --- | ||
| 59 | |||
| 60 | RPM-based Linux distributions should be able to create a package using | ||
| 61 | the included RPM spec file. Install the "rpm-build" package, or | ||
| 62 | similar, then: | ||
| 63 | |||
| 64 | # rpmbuild -tb lua-cjson-1.0.4.tar.gz | ||
| 65 | |||
| 66 | |||
| 67 | LuaRocks | ||
| 68 | -------- | ||
| 69 | |||
| 70 | LuaRocks (http://luarocks.org/) can be used to install and manage Lua | ||
| 71 | modules on a wide range of platforms (including Windows). | ||
| 72 | |||
| 73 | Extract the Lua CJSON source package into a directory and run: | ||
| 74 | |||
| 75 | # cd lua-cjson-1.0.4; luarocks make | ||
| 76 | |||
| 77 | LuaRocks does not support platform specific configuration for Solaris. | ||
| 78 | On Solaris, you may need to manually uncomment "USE_INTERNAL_ISINF" in | ||
| 79 | the rockspec before building this module. | ||
| 80 | |||
| 81 | See the LuaRocks documentation for further details. | ||
| 82 | |||
| 83 | |||
| 84 | Lua CJSON API | ||
| 85 | ============= | ||
| 86 | |||
| 87 | Synopsis | ||
| 88 | -------- | ||
| 89 | |||
| 90 | require "cjson" | ||
| 91 | -- Or: | ||
| 92 | local cjson = require "cjson" | ||
| 93 | |||
| 94 | -- Translate Lua value to/from JSON | ||
| 95 | text = cjson.encode(value) | ||
| 96 | value = cjson.decode(text) | ||
| 97 | |||
| 98 | -- Get and/or set CJSON configuration | ||
| 99 | setting = cjson.refuse_invalid_numbers([setting]) | ||
| 100 | depth = cjson.encode_max_depth([depth]) | ||
| 101 | convert, ratio, safe = cjson.encode_sparse_array([convert[, ratio[, safe]]]) | ||
| 102 | keep = cjson.encode_keep_buffer([keep]) | ||
| 103 | |||
| 104 | |||
| 105 | Encoding | ||
| 106 | -------- | ||
| 107 | |||
| 108 | json_text = cjson.encode(value) | ||
| 109 | |||
| 110 | cjson.encode() will serialise the following types: | ||
| 111 | * number, string, table, boolean, lightuserdata (NULL) or nil | ||
| 112 | |||
| 113 | The remaining Lua types cannot be serialised: | ||
| 114 | * thread, userdata, lightuserdata (non-NULL), function | ||
| 115 | |||
| 116 | Numbers are encoded using the standard Lua number format. | ||
| 117 | |||
| 118 | ASCII 0 - 31, double-quote, forward-slash, black-slash and ASCII 127 | ||
| 119 | are escaped when encoding strings. Other octets are passed | ||
| 120 | transparently. It is expected the application will perform UTF-8 error | ||
| 121 | checking if required. | ||
| 122 | |||
| 123 | A Lua table will only be recognised as an array if all keys are type | ||
| 124 | "number" and are positive integers (>0). Otherwise CJSON will encode | ||
| 125 | the table as a JSON object. | ||
| 126 | |||
| 127 | CJSON will also recognise and handle sparse arrays. Missing entries | ||
| 128 | will be encoded as "null". Eg: | ||
| 129 | { [3] = "data" } | ||
| 130 | becomes: | ||
| 131 | [null,null,"data"] | ||
| 132 | |||
| 133 | Note: standards compliant JSON must be encapsulated in either an | ||
| 134 | object ({}) or an array ([]). You must pass a table to cjson.encode() | ||
| 135 | if you want to generate standards compliant JSON output. | ||
| 136 | |||
| 137 | By default, errors will be raised for: | ||
| 138 | - Excessively sparse arrays (see below) | ||
| 139 | - More than 20 nested tables | ||
| 140 | - Invalid numbers (NaN, Infinity) | ||
| 141 | |||
| 142 | These defaults can be changed with: | ||
| 143 | - cjson.encode_sparse_array() | ||
| 144 | - cjson.encode_max_depth() | ||
| 145 | - cjson.refuse_invalid_numbers() | ||
| 146 | |||
| 147 | Example: | ||
| 148 | data_obj = { true, { foo = "bar" } } | ||
| 149 | data_json = cjson.encode(data_obj) | ||
| 150 | |||
| 151 | |||
| 152 | Decoding | ||
| 153 | -------- | ||
| 154 | |||
| 155 | value = cjson.decode(json_text) | ||
| 156 | |||
| 157 | cjson.decode() will deserialise any UTF-8 JSON string into a Lua data | ||
| 158 | structure. It can return any of the types that cjson.encode() | ||
| 159 | supports. | ||
| 160 | |||
| 161 | UTF-16 and UTF-32 JSON strings are not supported. | ||
| 162 | |||
| 163 | CJSON requires that NULL (\0) and double quote (\") are escaped within | ||
| 164 | strings. All escape codes will be decoded and other characters will be | ||
| 165 | passed transparently. UTF-8 characters are not validated during | ||
| 166 | decoding and should be checked elsewhere if required. | ||
| 167 | |||
| 168 | JSON "null" will be converted to a NULL lightuserdata value. This can | ||
| 169 | be compared with cjson.null for convenience. | ||
| 170 | |||
| 171 | By default, invalid numbers (NaN, Infinity, Hexidecimal) will be | ||
| 172 | decoded. | ||
| 173 | |||
| 174 | Example: | ||
| 175 | data_json = '[ true, { "foo": "bar" } ]' | ||
| 176 | data_obj = cjson.decode(data_json) | ||
| 177 | |||
| 178 | |||
| 179 | Invalid numbers | ||
| 180 | --------------- | ||
| 181 | |||
| 182 | setting = cjson.refuse_invalid_numbers([setting]) | ||
| 183 | -- "setting" must be on of: | ||
| 184 | -- false, "encode", "decode", "both", true | ||
| 185 | |||
| 186 | CJSON considers numbers which are outside the JSON specification to be | ||
| 187 | "invalid". Eg: | ||
| 188 | - Infinity | ||
| 189 | - NaN | ||
| 190 | - Hexadecimal numbers | ||
| 191 | |||
| 192 | By default CJSON will decode "invalid" numbers, but will refuse to | ||
| 193 | encode them. | ||
| 194 | |||
| 195 | This setting can be configured separately for encoding and/or | ||
| 196 | decoding: | ||
| 197 | - Enabled: an error will be generated if an invalid number is found. | ||
| 198 | - Disabled (encoding): NaN and Infinity can be encoded. | ||
| 199 | - Disabled (decoding): All numbers supported by strtod(3) will be | ||
| 200 | parsed. | ||
| 201 | |||
| 202 | |||
| 203 | Sparse arrays | ||
| 204 | ------------- | ||
| 205 | |||
| 206 | convert, ratio, safe = cjson.encode_sparse_array([convert[, ratio[, safe]]]) | ||
| 207 | -- "convert" must be a boolean. Default: false. | ||
| 208 | -- "ratio" must be a positive integer (>0). Default: 2 | ||
| 209 | -- "safe" must be a positive integer (>0). Default: 10 | ||
| 210 | |||
| 211 | A Lua array is sparse if it is missing a value for at least 1 index. | ||
| 212 | Lua CJSON encodes missing values as "null". Eg: | ||
| 213 | Lua array: { [3] = "sparse" } | ||
| 214 | JSON array: [null,null,"sparse"] | ||
| 215 | |||
| 216 | CJSON detects excessively sparse arrays by comparing the number of | ||
| 217 | items in a Lua array with the maximum index. In particular: | ||
| 218 | |||
| 219 | maximum index > safe AND maximum index > array_items * ratio | ||
| 220 | |||
| 221 | By default, attempting to encode excessively sparse arrays will | ||
| 222 | generate an error. | ||
| 223 | |||
| 224 | If "convert" is set to "true", excessively sparse arrays will be | ||
| 225 | encoded as a JSON object: | ||
| 226 | Lua array: { [1000] = "excessively sparse" } | ||
| 227 | JSON array: {"1000":"excessively sparse"} | ||
| 228 | |||
| 229 | Setting "ratio" to 0 disables checking for excessively sparse arrays. | ||
| 230 | |||
| 231 | |||
| 232 | Nested tables | ||
| 233 | ------------- | ||
| 234 | |||
| 235 | depth = cjson.encode_max_depth([depth]) | ||
| 236 | -- "depth" must be a positive integer (>0). | ||
| 237 | |||
| 238 | By default, CJSON will reject data structure with more than 20 nested | ||
| 239 | tables. | ||
| 240 | |||
| 241 | This check is used to prevent a nested data structure from crashing | ||
| 242 | the application. Eg: | ||
| 243 | a = {}; b = { a }; a[1] = b | ||
| 244 | |||
| 245 | |||
| 246 | Number precision | ||
| 247 | ---------------- | ||
| 248 | |||
| 249 | precision = cjson.encode_number_precision([precision]) | ||
| 250 | -- "precision" must be between 1 and 14 (inclusive) | ||
| 251 | |||
| 252 | By default CJSON will output 14 significant digits when converting a | ||
| 253 | number to text. | ||
| 254 | |||
| 255 | Reducing number precision to 3 can improve performance of number | ||
| 256 | heavy conversions by up to 50%. | ||
| 257 | |||
| 258 | |||
| 259 | Persistent encoding buffer | ||
| 260 | -------------------------- | ||
| 261 | |||
| 262 | keep = cjson.keep_encode_buffer([keep]) | ||
| 263 | -- "keep" must be a boolean | ||
| 264 | |||
| 265 | By default, CJSON will reuse the JSON encoding buffer to improve | ||
| 266 | performance. The buffer will grow to the largest size required and is | ||
| 267 | not freed until CJSON is garbage collected. Setting this option to | ||
| 268 | "false" will cause the buffer to be freed after each call to | ||
| 269 | cjson.encode(). | ||
| 270 | |||
| 271 | |||
| 272 | JSON and handling under Lua CJSON | ||
| 273 | ================================= | ||
| 274 | |||
| 275 | Nulls | ||
| 276 | ----- | ||
| 277 | |||
| 278 | Lua CJSON decodes JSON "null" as a Lua lightuserdata NULL pointer. | ||
| 279 | |||
| 280 | As a convenience, "cjson.null" is provided for comparison. | ||
| 281 | |||
| 282 | |||
| 283 | Table keys | ||
| 284 | ---------- | ||
| 285 | |||
| 286 | JSON object keys must be strings - other types are not supported. Lua | ||
| 287 | CJSON will convert numeric keys to a string, and other non-string | ||
| 288 | types will generate an error. | ||
| 289 | |||
| 290 | JSON object keys are always be decoded as Lua strings. | ||
| 291 | |||
| 292 | If all Lua table keys are numbers (not strings), Lua CJSON will | ||
| 293 | encode the table as a JSON array. See "Sparse arrays" above for | ||
| 294 | more details. | ||
| 295 | |||
| 296 | |||
| 297 | Metamethods | ||
| 298 | ----------- | ||
| 299 | |||
| 300 | Lua CJSON does not use metamethods when serialising tables. | ||
| 301 | - next() is used to iterate over tables. | ||
| 302 | - rawget() is used to iterate over arrays. | ||
| 303 | |||
| 304 | |||
| 305 | Functions, Userdata, Threads | ||
| 306 | ---------------------------- | ||
| 307 | |||
| 308 | Lua CJSON will generate an error if asked to serialise Lua functions, | ||
| 309 | userdata, lightuserdata or threads. | ||
| 310 | |||
| 311 | |||
| 312 | Locales | ||
| 313 | ------- | ||
| 314 | |||
| 315 | Lua CJSON uses strtod() and snprintf() to perform numeric conversion | ||
| 316 | as they are usually well supported, fast and bug free. | ||
| 317 | |||
| 318 | To ensure JSON encoding/decoding works correctly for locales using | ||
| 319 | comma decimal separators, Lua CJSON must be compiled with either | ||
| 320 | USE_POSIX_USELOCALE or USE_POSIX_SETLOCALE. See the Makefile or the | ||
| 321 | rockspec for details. | ||
| 322 | |||
| 323 | |||
| 324 | References | ||
| 325 | ========== | ||
| 326 | |||
| 327 | - http://tools.ietf.org/html/rfc4627 | ||
| 328 | - http://www.json.org/ | ||
