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