Composer 镜像原理 (2) —— composer.json
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有使用PHP组件的朋友, 应该会注意到组件里头会有一个文件 composer.json, 它描述了组件的信息: 名称, 描述, 关键词, 作者, GitHub仓库地址...还有它所依赖的子组件, 是 Composer 工作的核心.
拿一个大家都知道的日志组件 monolog 的 composer.json 为例, 我说下一些比较重要的字段:
{
"name": "monolog/monolog",
"description": "Sends your logs to files, sockets, inboxes, databases and various web services",
"keywords": ["log", "logging", "psr-3"],
"homepage": "http://github.com/Seldaek/monolog",
"type": "library",
"license": "MIT",
"authors": [
{
"name": "Jordi Boggiano",
"email": "j.boggiano@seld.be",
"homepage": "http://seld.be"
}
],
"require": {
"php": "^7.0",
"psr/log": "^1.0.1"
},
"require-dev": {
"phpunit/phpunit": "^5.7",
"graylog2/gelf-php": "^1.4.2",
"sentry/sentry": "^0.13",
"ruflin/elastica": ">=0.90 <3.0",
"doctrine/couchdb": "~1.0@dev",
"aws/aws-sdk-php": "^2.4.9 || ^3.0",
"php-amqplib/php-amqplib": "~2.4",
"swiftmailer/swiftmailer": "^5.3|^6.0",
"php-console/php-console": "^3.1.3",
"jakub-onderka/php-parallel-lint": "^0.9",
"predis/predis": "^1.1",
"phpspec/prophecy": "^1.6.1"
},
"suggest": {
"graylog2/gelf-php": "Allow sending log messages to a GrayLog2 server",
"sentry/sentry": "Allow sending log messages to a Sentry server",
"doctrine/couchdb": "Allow sending log messages to a CouchDB server",
"ruflin/elastica": "Allow sending log messages to an Elastic Search server",
"php-amqplib/php-amqplib": "Allow sending log messages to an AMQP server using php-amqplib",
"ext-amqp": "Allow sending log messages to an AMQP server (1.0+ required)",
"ext-mongodb": "Allow sending log messages to a MongoDB server (via driver)",
"mongodb/mongodb": "Allow sending log messages to a MongoDB server (via library)",
"aws/aws-sdk-php": "Allow sending log messages to AWS services like DynamoDB",
"rollbar/rollbar": "Allow sending log messages to Rollbar",
"php-console/php-console": "Allow sending log messages to Google Chrome"
},
"autoload": {
"psr-4": {"Monolog\\": "src/Monolog"}
},
"autoload-dev": {
"psr-4": {"Monolog\\": "tests/Monolog"}
},
"provide": {
"psr/log-implementation": "1.0.0"
},
"extra": {
"branch-alias": {
"dev-master": "2.0.x-dev"
}
},
"scripts": {
"test": [
"parallel-lint . --exclude vendor",
"phpunit"
]
}
}
安装依赖的时候, 最重要的字段是 name, require 以及 require-dev.
name
该字段标识了组件的名称, 在 所有 的组件中, 它是唯一的;
require
该字段列举出该组件 所需的运行环境 以及 依赖的子组件的版本, 安装该组件时, 会检测运行环境, 并安装该组件的子组件, 以及这些子组件的所有子组件...直到子组件不再依赖任何组件为止;
require-dev
该字段不是必须的, 一般来说不安装里面的依赖, 也是可以用的, 通常都是用来跑单元测试. 依赖的安装同 require 字段.
其他字段对于理解镜像的原理没什么帮助, 有兴趣可以看下 这篇文章.
安装依赖的过程, 其实就是请求服务器, 要求拿到该组件的 composer.json 文件, 然后 JSON 解析, 得到 require 和 require-dev 字段的组件, 一直遍历下去, 根据文件描述的仓库地址 git clone 到本地.
看过我 上一篇文章 的朋友就知道, 文章末尾我们配置了 国内的composer镜像, 用来加速我们安装组件的过程, 它缓存了所有包的 composer.json, 并把仓库的每一个分支源码, 打包为 zip 压缩包, 并结合 cdn 加速.
镜像服务器提供了让我们得到 composer.json 的接口, 我们只需提交一个包名, 还有请求结果的哈希值(是不是很懵逼, 我怎么知道结果的哈希值), 镜像服务器会返回一个 JSON, 它包含了很多 composer.json (至少一个), 这些 composer.json 里面就有我们要找的组件的 composer.json (根据name字段), 也包括了其他包的, 为什么会带有其他包的呢, 我捣鼓了挺多次, 发现是当 require 字段存在时, 它就顺带返回了, 不过也不是绝对的, 可能考虑体积关系, 也不会返回太多.
说了这么多, 看下 psr/log 组件的请求结果吧, 比较长, 它包含了5个包的信息:
hackification/log
mobio/target
notadd/wechat
psr/log
wedeto/log
{
"packages":{
"hackification/log":{
"1.0.2":{
"name":"hackification/log",
"description":"Common interface for logging libraries",
"keywords":[
"log",
"psr",
"psr-3",
"hack",
"hacklang"
],
"homepage":"https://github.com/hackification/log",
"version":"1.0.2",
"version_normalized":"1.0.2.0",
"license":[
"MIT"
],
"authors":[
{
"name":"PHP-FIG",
"homepage":"http://www.php-fig.org/"
}
],
"source":{
"type":"git",
"url":"https://github.com/hackification/log.git",
"reference":"75b02e14bd8e5b8ded75de91d7eb9df6046f7fa7"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/hackification/log/75b02e14bd8e5b8ded75de91d7eb9df6046f7fa7.zip",
"reference":"75b02e14bd8e5b8ded75de91d7eb9df6046f7fa7",
"shasum":""
},
"type":"library",
"time":"2016-11-08T15:32:34+00:00",
"autoload":{
"psr-4":{
"Psr\Log\":"Psr/Log/"
}
},
"extra":{
"branch-alias":{
"dev-master":"1.0.x-dev"
}
},
"require":{
"hhvm":">=3.0.0"
},
"replace":{
"psr/log":"*"
},
"uid":1072563
},
"dev-master":{
"name":"hackification/log",
"description":"Common interface for logging libraries",
"keywords":[
"log",
"psr",
"psr-3",
"hack",
"hacklang"
],
"homepage":"https://github.com/hackification/log",
"version":"dev-master",
"version_normalized":"9999999-dev",
"license":[
"MIT"
],
"authors":[
{
"name":"PHP-FIG",
"homepage":"http://www.php-fig.org/"
}
],
"source":{
"type":"git",
"url":"https://github.com/hackification/log.git",
"reference":"75b02e14bd8e5b8ded75de91d7eb9df6046f7fa7"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/hackification/log/75b02e14bd8e5b8ded75de91d7eb9df6046f7fa7.zip",
"reference":"75b02e14bd8e5b8ded75de91d7eb9df6046f7fa7",
"shasum":""
},
"type":"library",
"time":"2016-11-08T15:32:34+00:00",
"autoload":{
"psr-4":{
"Psr\Log\":"Psr/Log/"
}
},
"extra":{
"branch-alias":{
"dev-master":"1.0.x-dev"
}
},
"require":{
"hhvm":">=3.0.0"
},
"replace":{
"psr/log":"*"
},
"uid":1072564
}
},
"mobio/target":{
"0.0.5":{
"name":"mobio/target",
"description":"PHP library for myTarget API",
"keywords":[
"php",
"myTarget"
],
"homepage":"",
"version":"0.0.5",
"version_normalized":"0.0.5.0",
"license":[
"MIT"
],
"authors":[
],
"source":{
"type":"git",
"url":"https://github.com/MobioInc/target.git",
"reference":"5baeaae1aa7d85c5b5fd4e33a06608a1de93d73b"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/MobioInc/target/5baeaae1aa7d85c5b5fd4e33a06608a1de93d73b.zip",
"reference":"5baeaae1aa7d85c5b5fd4e33a06608a1de93d73b",
"shasum":""
},
"type":"library",
"time":"2016-10-31T08:52:52+00:00",
"autoload":{
"psr-4":{
"Mobio\Target\":"src/"
}
},
"require":{
"php":">=5.5.0",
"psr/log":"~1.0",
"guzzlehttp/guzzle":"^6.1"
},
"require-dev":{
"phpunit/phpunit":"^5.5"
},
"provide":{
"psr/log":"1.0.0"
},
"uid":1060012
},
"dev-master":{
"name":"mobio/target",
"description":"PHP library for myTarget API",
"keywords":[
"php",
"myTarget"
],
"homepage":"",
"version":"dev-master",
"version_normalized":"9999999-dev",
"license":[
"MIT"
],
"authors":[
],
"source":{
"type":"git",
"url":"https://github.com/MobioInc/target.git",
"reference":"70aa382ca6d3ba3b5a834bbe85d3fc2cbfec965f"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/MobioInc/target/70aa382ca6d3ba3b5a834bbe85d3fc2cbfec965f.zip",
"reference":"70aa382ca6d3ba3b5a834bbe85d3fc2cbfec965f",
"shasum":""
},
"type":"library",
"time":"2017-02-13T18:53:10+00:00",
"autoload":{
"psr-4":{
"Mobio\Target\":"src/"
}
},
"require":{
"php":">=5.5.0",
"guzzlehttp/guzzle":"^6.1",
"psr/log":"~1.0"
},
"require-dev":{
"phpunit/phpunit":"^5.5"
},
"provide":{
"psr/log":"1.0.0"
},
"uid":700331
}
},
"notadd/wechat":{
"dev-master":{
"name":"notadd/wechat",
"description":"Notadd's Wechat Module.",
"keywords":[
"framework",
"cms",
"member",
"notadd"
],
"homepage":"https://notadd.com",
"version":"dev-master",
"version_normalized":"9999999-dev",
"license":[
"Apache-2.0"
],
"authors":[
{
"name":"Notadd",
"email":"notadd@ibenchu.com"
}
],
"source":{
"type":"git",
"url":"https://github.com/notadd/wechat.git",
"reference":"e3f684cd225f3fadf21953c0289cb8426baad0e5"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/notadd/wechat/e3f684cd225f3fadf21953c0289cb8426baad0e5.zip",
"reference":"e3f684cd225f3fadf21953c0289cb8426baad0e5",
"shasum":""
},
"type":"notadd-module",
"time":"2017-11-13T04:23:05+00:00",
"autoload":{
"psr-4":{
"Notadd\Wechat\":"src/"
}
},
"require":{
"php":">=7.0",
"overtrue/wechat":"~3.1"
},
"require-dev":{
"notadd/installers":"0.14.*",
"notadd/testing":"0.4.*",
"phpunit/phpunit":"~6.0"
},
"replace":{
"guzzlehttp/guzzle":"*",
"guzzlehttp/promises":"*",
"guzzlehttp/psr7":"*",
"monolog/monolog":"*",
"psr/container":"*",
"psr/http-message":"*",
"psr/log":"*",
"symfony/http-foundation":"*",
"symfony/polyfill-mbstring":"*",
"symfony/psr-http-message-bridge":"*"
},
"uid":1108963
}
},
"psr/log":{
"1.0.0":{
"name":"psr/log",
"description":"Common interface for logging libraries",
"keywords":[
"log",
"psr",
"psr-3"
],
"homepage":"",
"version":"1.0.0",
"version_normalized":"1.0.0.0",
"license":[
"MIT"
],
"authors":[
{
"name":"PHP-FIG",
"homepage":"http://www.php-fig.org/"
}
],
"source":{
"type":"git",
"url":"https://github.com/php-fig/log.git",
"reference":"fe0936ee26643249e916849d48e3a51d5f5e278b"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/php-fig/log/fe0936ee26643249e916849d48e3a51d5f5e278b.zip",
"reference":"fe0936ee26643249e916849d48e3a51d5f5e278b",
"shasum":""
},
"type":"library",
"time":"2012-12-21T11:40:51+00:00",
"autoload":{
"psr-0":{
"Psr\Log\":""
}
},
"uid":29358
},
"1.0.1":{
"name":"psr/log",
"description":"Common interface for logging libraries",
"keywords":[
"log",
"psr",
"psr-3"
],
"homepage":"https://github.com/php-fig/log",
"version":"1.0.1",
"version_normalized":"1.0.1.0",
"license":[
"MIT"
],
"authors":[
{
"name":"PHP-FIG",
"homepage":"http://www.php-fig.org/"
}
],
"source":{
"type":"git",
"url":"https://github.com/php-fig/log.git",
"reference":"5277094ed527a1c4477177d102fe4c53551953e0"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/php-fig/log/5277094ed527a1c4477177d102fe4c53551953e0.zip",
"reference":"5277094ed527a1c4477177d102fe4c53551953e0",
"shasum":""
},
"type":"library",
"time":"2016-09-19T16:02:08+00:00",
"autoload":{
"psr-4":{
"Psr\Log\":"Psr/Log/"
}
},
"extra":{
"branch-alias":{
"dev-master":"1.0.x-dev"
}
},
"require":{
"php":">=5.3.0"
},
"uid":1000789
},
"1.0.2":{
"name":"psr/log",
"description":"Common interface for logging libraries",
"keywords":[
"log",
"psr",
"psr-3"
],
"homepage":"https://github.com/php-fig/log",
"version":"1.0.2",
"version_normalized":"1.0.2.0",
"license":[
"MIT"
],
"authors":[
{
"name":"PHP-FIG",
"homepage":"http://www.php-fig.org/"
}
],
"source":{
"type":"git",
"url":"https://github.com/php-fig/log.git",
"reference":"4ebe3a8bf773a19edfe0a84b6585ba3d401b724d"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/php-fig/log/4ebe3a8bf773a19edfe0a84b6585ba3d401b724d.zip",
"reference":"4ebe3a8bf773a19edfe0a84b6585ba3d401b724d",
"shasum":""
},
"type":"library",
"time":"2016-10-10T12:19:37+00:00",
"autoload":{
"psr-4":{
"Psr\Log\":"Psr/Log/"
}
},
"extra":{
"branch-alias":{
"dev-master":"1.0.x-dev"
}
},
"require":{
"php":">=5.3.0"
},
"uid":1029935
},
"dev-master":{
"name":"psr/log",
"description":"Common interface for logging libraries",
"keywords":[
"log",
"psr",
"psr-3"
],
"homepage":"https://github.com/php-fig/log",
"version":"dev-master",
"version_normalized":"9999999-dev",
"license":[
"MIT"
],
"authors":[
{
"name":"PHP-FIG",
"homepage":"http://www.php-fig.org/"
}
],
"source":{
"type":"git",
"url":"https://github.com/php-fig/log.git",
"reference":"4ebe3a8bf773a19edfe0a84b6585ba3d401b724d"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/php-fig/log/4ebe3a8bf773a19edfe0a84b6585ba3d401b724d.zip",
"reference":"4ebe3a8bf773a19edfe0a84b6585ba3d401b724d",
"shasum":""
},
"type":"library",
"time":"2016-10-10T12:19:37+00:00",
"autoload":{
"psr-4":{
"Psr\Log\":"Psr/Log/"
}
},
"extra":{
"branch-alias":{
"dev-master":"1.0.x-dev"
}
},
"require":{
"php":">=5.3.0"
},
"uid":29285
}
},
"wedeto/log":{
"v0.9.1":{
"name":"wedeto/log",
"description":"Wedeto Platform - Logger",
"keywords":[
],
"homepage":"https://wedeto.net/",
"version":"v0.9.1",
"version_normalized":"0.9.1.0",
"license":[
"MIT"
],
"authors":[
{
"name":"Egbert van der Wal",
"email":"ewal@pointpro.nl"
}
],
"source":{
"type":"git",
"url":"https://github.com/Wedeto/Log.git",
"reference":"acc7f4aa66965dd2627a3886c9ac8b0d77b0a268"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/Wedeto/Log/acc7f4aa66965dd2627a3886c9ac8b0d77b0a268.zip",
"reference":"acc7f4aa66965dd2627a3886c9ac8b0d77b0a268",
"shasum":""
},
"type":"library",
"time":"2017-04-10T12:31:55+00:00",
"autoload":{
"psr-4":{
"Wedeto\Log\":"src/"
}
},
"require":{
"psr/log":"1.0.*",
"wedeto/util":"0.9.*",
"php":">=7.0.0"
},
"require-dev":{
"mikey179/vfsstream":"~1"
},
"provide":{
"psr/log":"1.0.*"
},
"uid":1336127
},
"v0.9.2":{
"name":"wedeto/log",
"description":"Wedeto Platform - Logger",
"keywords":[
],
"homepage":"https://wedeto.net/",
"version":"v0.9.2",
"version_normalized":"0.9.2.0",
"license":[
"MIT"
],
"authors":[
{
"name":"Egbert van der Wal",
"email":"ewal@pointpro.nl"
}
],
"source":{
"type":"git",
"url":"https://github.com/Wedeto/Log.git",
"reference":"55e6b03f0b446b7054078fd8a680ad1499d26264"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/Wedeto/Log/55e6b03f0b446b7054078fd8a680ad1499d26264.zip",
"reference":"55e6b03f0b446b7054078fd8a680ad1499d26264",
"shasum":""
},
"type":"library",
"time":"2017-04-10T18:15:36+00:00",
"autoload":{
"psr-4":{
"Wedeto\Log\":"src/"
}
},
"require":{
"psr/log":"1.0.*",
"wedeto/util":"0.9.*",
"php":">=7.0.0"
},
"require-dev":{
"mikey179/vfsstream":"~1"
},
"provide":{
"psr/log":"1.0.*"
},
"uid":1336697
}
}
}
}
可以看到, packages 字段里面有5个包, 里面的 psr/log 字段就是我们要找的, 而里面有各个分支的 composer.json, 以分支 1.0.0 为例, 里面有两个很关键的字段, source 和 dist:
{
"source":{
"type":"git",
"url":"https://github.com/php-fig/log.git",
"reference":"fe0936ee26643249e916849d48e3a51d5f5e278b"
},
"dist":{
"type":"zip",
"url":"https://files.phpcomposer.com/files/php-fig/log/fe0936ee26643249e916849d48e3a51d5f5e278b.zip",
"reference":"fe0936ee26643249e916849d48e3a51d5f5e278b",
"shasum":""
}
}
dist
该字段其实就是加速的 zip 压缩包, 无需 git clone, 只需把 zip 下载到本地, 解压完, 分支 1.0.0 就装好了.
source
这个字段的作用, 就是万一 dist 字段的 zip 下载不了, 不会马上中断整个安装流程, 而是接着 git clone. 也就是说, dist 字段失败, 或者压根就没有 dist 字段, 就走 source 字段.
看到这里, 对 Composer 的了解应该多了很多吧? 还记得 请求结果的哈希值 吗? 这个哈希哪里来的, 为什么我可以提前知道这个请求的 JSON 的哈希值? 还有, 接口在哪里? 镜像服务器的官方网站, 并没有提供啊...
下一篇文章再告诉你.
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文章来源于本人博客，发布于 2017-12-05，原文链接：imlht.com/archives/81…
转载自:https://juejin.cn/post/7192452926508367928