--- a/lib/Protobuf-PHP/README.md +++ b/lib/Protobuf-PHP/README.md @@ -1,1 +1,198 @@ +Protobuf for PHP +================ +Protobuf for PHP is an implementation of Google's Protocol Buffers for the PHP +language, supporting its binary data serialization and including a `protoc` +plugin to generate PHP classes from .proto files. + +Great effort has been put into generating PHP files that include all sort of type +hints to aide IDE's with autocompletion. Therefore, it can not only be used to +communicate with Protocol Buffers services but also as a generation tool for +_data objects_ no matter what the final serialization is. + +For more information see the [included man pages](http://drslump.github.com/Protobuf-PHP/). + + +## Requirements + + - PHP 5.3 + - Pear's Console_CommandLine (for the protoc wrapper tool) + - Google's `protoc` compiler version 2.3 or above + - GMP or BC Math extensions ¹ + + ¹ Only needed for negative values in `int32`, `int64` or `fixed64` types. See + the _known issues_ section. + + +## Features + +### Working + + - Standard types (numbers, string, enums, messages, etc) + - Pluggable serialization backends (codecs) + - Standard Binary + - Standard TextFormat ¹ + - PhpArray + - JSON + - [ProtoJson](https://github.com/drslump/ProtoJson) (_TagMap_ and _Indexed_ variants) + - XML + - Protoc compiler plugin to generate the PHP classes + - Extensions + - Unknown fields + - Packed fields + - Reflection + - Dynamic messages with annotations support + - Generates service interfaces + - Includes comments from .proto files in the generated files + - Pear package for easy installation + +¹ Only serialization is supported + +### Future + + - Speed optimized code generation mode + - Support numbers beyond PHP's native limits + + + +## Example usage + + $person = new Tutorial\Person(); + $person->name = 'DrSlump'; + $person->setId(12); + + $book = new Tutorial\AddressBook(); + $book->addPerson($person); + + // Use default codec + $data = $book->serialize(); + + // Use custom codec + $codec = new \DrSlump\Protobuf\Codec\Binary(); + $data = $codec->encode($book); + // ... or ... + $data = $book->serialize($codec); + + +## Installation + +Install with Pear + + pear channel-discover pear.pollinimini.net + pear install drslump/Protobuf-beta + +You can also get the latest version by checking out a copy of the +repository in your computer. + + + +## Known issues + + +### Types + +PHP is very weak when dealing with numbers processing. Several work arounds have been applied +to the standard binary codec to reduce incompatibilities between Protobuf types and PHP ones. + + - Protobuf stores floating point values using the [IEEE 754](http://en.wikipedia.org/wiki/IEEE_754) standard + with 64bit words for the `double` and 32bit for the `float` types. PHP supports IEEE 754 natively although + the precission is platform dependant, however it typically supports 64bit doubles. It means that + if your PHP was compiled with 64bit sized doubles (or greater) you shouldn't have any problem encoding + and decoded float and double typed values with Protobuf. + + - Integer values are also [platform dependant in PHP](http://www.php.net/manual/en/language.types.integer.php). + The library has been developed and tested against PHP binaries compiled with 64bit integers. The encoding and + decoding algorithm should in theory work no matter if PHP uses 32bit or 64bit integers internally, just take + into account that with 32bit integers the numbers cannot exceed in any case the `PHP_INT_MAX` value (2147483647). + + While Protobuf supports unsigned integers PHP does not. In fact, numbers above the compiled PHP maximum + integer (`PHP_INT_MAX`, 0x7FFFFFFFFFFFFFFF for 64bits) will be automatically casted to doubles, which + typically will offer 53bits of decimal precission, allowing to safely work with numbers upto + 0x20000000000000 (2^53), even if they are represented in PHP as floats instead of integers. Higher numbers + will loose precission or might even return an _infinity_ value, note that the library does not include + any checking for these numbers and using them might provoke unexpected behaviour. + + Negative values when encoded as `int32`, `int64` or `fixed64` types require the big integer extensions + [GMP](http://www.php.net/gmp) or [BC Math](http://www.php.net/bc) (the later only for 64bit architectures) + to be available in your PHP environment. The reason is that when encoding these negative numbers without + using _zigzag_ the binary representation uses the most significant bit for the sign, thus the numbers become + above the maximum supported values in PHP. The library will check for these conditions and will automatically + try to use GMP or BC to process the value. + + +### Strings + +The binary codec expects strings to be encoded using UTF-8. PHP does not natively support string encodings, +PHP's string data type is basically a length delimited stream of bytes, so it's not trivial to include +automatic encoding conversion into the library encoding and decoding routines. Instead of trying to guess +or offer a configuration interface for the encoding, the binary codec will process the `string` type just as +it would process `byte` one, delegating on your application the task of encoding or decoding in the desired +character set. + +### Memory usage + +Large messages might be troublesome since the way the library is modelled does not allow to parse or +serialize messages as a streams, instead the whole operation is performed in memory, which allows for faster +processing but could consume too much RAM if messages are too large. + + +### Unknown fields + +Since wire types are different across different codec's formats, it's not possible to transcode unkwnon +fields consumed in one codec to another. This means, for example, that when consuming a message using the +binary codec, if it contains unknown fields, they won't be included when serializing the message using the +Json codec. + + +## Generating PHP classes + +The generation tool is designed to be run as a `protoc` plugin, thus it should +work with any proto file supported by the official compiler. + + protoc --plugin=protoc-gen-php --php_out=./build tutorial.proto + +To make use of non-standard options in your proto files (like `php.namespace`) you'll +have to import the `php.proto` file included with the library. It's location will +depend on where you've installed this library. + + protoc -I=./Protobuf-PHP/library/DrSlump/Protobuf/Compiler/protos \ + --plugin=protoc-gen-php --php_out=./build tutorial.proto + +In order to make your life easier, the supplied protoc plugin offers an additional +execution mode, where it acts as a wrapper for the `protoc` invocation. It will +automatically include the `php.proto` path so that you don't need to worry about it. + + protoc-gen-php -o ./build tutorial.proto + + +## LICENSE: + + The MIT License + + Copyright (c) 2011 Iván -DrSlump- Montes + + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + 'Software'), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, subject to + the following conditions: + + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY + CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, + TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + + + + + + +