nrm的使用与源码分析

秒速五厘米 2022-05-27 09:41 314阅读 0赞

##### 一、nrm的使用 #####

.在使用npm进行项目拉取的时候，我们可能会进行切换不同的镜像去下载,下面这个就是快速切换镜像的插件  
[快速切换npm源的开源工具nrm-github地址][npm_nrm-github]  
[快速切换npm源的开源工具–nrm][npm_nrm]  
在这里我们对nrm源码进行查看：  
1.如下所示，nrm源码结构  
![nrm源码][nrm]  
在上面源码中，各个文件对应意义如下所示：

.gitignore--------------------git上传文件时的忽略文件
    cli.js------------------------nrm项目的主要代码
    package.json------------------npm项目配置文件
    registries.json---------------已经注册过的镜像地址，可以进行拉取包的镜像

2.cli.js文件说明  
首先来看一下代码内容

#!/usr/bin/env node
    var path = require('path');
    var fs = require('fs');
    var program = require('commander');
    var npm = require('npm');
    var ini = require('ini');
    var echo = require('node-echo');
    var extend = require('extend');
    var open = require('open');
    var async = require('async');
    var request = require('request');
    var only = require('only');
    
    var registries = require('./registries.json');
    var PKG = require('./package.json');
    var NRMRC = path.join(process.env.HOME, '.nrmrc');
    program
        .version(PKG.version);
    program
        .command('ls')
        .description('List all the registries')
        .action(onList);
    program
        .command('current')
        .description('Show current registry name')
        .action(showCurrent);
    program
        .command('use <registry>')
        .description('Change registry to registry')
        .action(onUse);
    program
        .command('add <registry> <url> [home]')
        .description('Add one custom registry')
        .action(onAdd);
    program
        .command('del <registry>')
        .description('Delete one custom registry')
        .action(onDel);
    program
        .command('home <registry> [browser]')
        .description('Open the homepage of registry with optional browser')
        .action(onHome);
    program
        .command('test [registry]')
        .description('Show response time for specific or all registries')
        .action(onTest);
    program
        .command('help')
        .description('Print this help')
        .action(function () { 
            program.outputHelp();
        });
    program
        .parse(process.argv);
    if (process.argv.length === 2) {
        program.outputHelp();
    }
    /* cmd methods /*/
    function onList() { 
        getCurrentRegistry(function(cur) { 
            var info = [''];
            var allRegistries = getAllRegistry();
            Object.keys(allRegistries).forEach(function(key) { 
                var item = allRegistries[key];
                var prefix = item.registry === cur ? '* ' : ' ';
                info.push(prefix + key + line(key, 8) + item.registry);
            });
            info.push('');
            printMsg(info);
        });
    }
    function showCurrent() { 
        getCurrentRegistry(function(cur) { 
            var allRegistries = getAllRegistry();
            Object.keys(allRegistries).forEach(function(key) { 
                var item = allRegistries[key];
                if (item.registry === cur) {
                    printMsg([key]);
                    return;
                }
            });
        });
    }
    function onUse(name) { 
        var allRegistries = getAllRegistry();
        if (allRegistries.hasOwnProperty(name)) {
            var registry = allRegistries[name];
            npm.load(function (err) { 
                if (err) return exit(err);
                npm.commands.config(['set', 'registry', registry.registry], function (err, data) { 
                    if (err) return exit(err);
                    console.log(' ');
                    var newR = npm.config.get('registry');
                    printMsg([
                        '', ' Registry has been set to: ' + newR, ''
                    ]);
                })
            });
        } else {
            printMsg([
                '', ' Not find registry: ' + name, ''
            ]);
        }
    }
    function onDel(name) { 
        var customRegistries = getCustomRegistry();
        if (!customRegistries.hasOwnProperty(name)) return;
        getCurrentRegistry(function(cur) { 
            if (cur === customRegistries[name].registry) {
                onUse('npm');
            }
            delete customRegistries[name];
            setCustomRegistry(customRegistries, function(err) { 
                if (err) return exit(err);
                printMsg([
                    '', ' delete registry ' + name + ' success', ''
                ]);
            });
        });
    }
    function onAdd(name, url, home) { 
        var customRegistries = getCustomRegistry();
        if (customRegistries.hasOwnProperty(name)) return;
        var config = customRegistries[name] = {};
        if (url[url.length - 1] !== '/') url += '/'; // ensure url end with /
        config.registry = url;
        if (home) {
            config.home = home;
        }
        setCustomRegistry(customRegistries, function(err) { 
            if (err) return exit(err);
            printMsg([
                '', ' add registry ' + name + ' success', ''
            ]);
        });
    }
    function onHome(name, browser) { 
        var allRegistries = getAllRegistry();
        var home = allRegistries[name] && allRegistries[name].home;
        if (home) {
            var args = [home];
            if (browser) args.push(browser);
            open.apply(null, args);
        }
    }
    function onTest(registry) { 
        var allRegistries = getAllRegistry();
        var toTest;
        if (registry) {
            if (!allRegistries.hasOwnProperty(registry)) {
                return;
            }
            toTest = only(allRegistries, registry);
        } else {
            toTest = allRegistries;
        }
        async.map(Object.keys(toTest), function(name, cbk) { 
            var registry = toTest[name];
            var start = +new Date();
            request(registry.registry + 'pedding', function(error) { 
                cbk(null, {
                    name: name,
                    registry: registry.registry,
                    time: (+new Date() - start),
                    error: error ? true : false
                });
            });
        }, function(err, results) { 
            getCurrentRegistry(function(cur) { 
                var msg = [''];
                results.forEach(function(result) { 
                    var prefix = result.registry === cur ? '* ' : ' ';
                    var suffix = result.error ? 'Fetch Error' : result.time + 'ms';
                    msg.push(prefix + result.name + line(result.name, 8) + suffix);
                });
                msg.push('');
                printMsg(msg);
            });
        });
    }
    /* helper methods /*/
    /* * get current registry */
    function getCurrentRegistry(cbk) { 
        npm.load(function(err, conf) { 
            if (err) return exit(err);
            cbk(npm.config.get('registry'));
        });
    }
    function getCustomRegistry() { 
        return fs.existsSync(NRMRC) ? ini.parse(fs.readFileSync(NRMRC, 'utf-8')) : {};
    }
    function setCustomRegistry(config, cbk) { 
        echo(ini.stringify(config), '>', NRMRC, cbk);
    }
    function getAllRegistry() { 
        return extend({}, registries, getCustomRegistry());
    }
    function printErr(err) { 
        console.error('an error occured: ' + err);
    }
    function printMsg(infos) { 
        infos.forEach(function(info) { 
            console.log(info);
        });
    }
    /* * print message & exit */
    function exit(err) { 
        printErr(err);
        process.exit(1);
    }
    function line(str, len) { 
        var line = new Array(Math.max(1, len - str.length)).join('-');
        return ' ' + line + ' ';
    }

###### 如下代码，进行引入使用的依赖包 ######

上面代码中，第一行这种用法是为了防止操作系统用户没有将node装在默认的/usr/bin路径里。当系统看到这一行的时候，首先会到env设置里查找node的安装路径，再调用对应路径下的解释器程序完成操作。  
commander包是npm依赖排名前十之一的模块，主要作用为命令行辅助工具  
registries注册的npm镜像  
PKG是package.json文件，在这里用于获取包的版本号  
NRMRC是npm配置文件的位置，用于写入npm配置信息，里边就包含npm镜像的地址位置

###### 如下代码，能够使用的命令行代码 ######

program
        .version(PKG.version); //package包的版本
    program
        .command('ls') //可以输入的命令ls
        .description('List all the registries')//描述性信息
        .action(onList); //调用该命令行对应的方法
    program
        .command('current')//可以输入的命令ls
        .description('Show current registry name')//描述性信息
        .action(showCurrent); //调用的方法名，对应后面自己写的方法名，在该方法中进行该命令行对应的代码功能
    program
        .command('use <registry>')
        .description('Change registry to registry')
        .action(onUse);
    program
        .command('add <registry> <url> [home]')
        .description('Add one custom registry')
        .action(onAdd);
    program
        .command('del <registry>')
        .description('Delete one custom registry')
        .action(onDel);
    program
        .command('home <registry> [browser]')
        .description('Open the homepage of registry with optional browser')
        .action(onHome);
    program
        .command('test [registry]')
        .description('Show response time for specific or all registries')
        .action(onTest);
    program
        .command('help')
        .description('Print this help')
        .action(function () { program.outputHelp(); });
    program
        .parse(process.argv);
    if (process.argv.length === 2) { program.outputHelp(); }

###### 命令行调用的方法 ######

/* cmd methods /*/
    function onList() { //展示镜像列表的方法，对应上面命令行代码中action调用的方法名
        getCurrentRegistry(function(cur) { 
            var info = [''];
            var allRegistries = getAllRegistry();
            Object.keys(allRegistries).forEach(function(key) { 
                var item = allRegistries[key];
                var prefix = item.registry === cur ? '* ' : ' ';
                info.push(prefix + key + line(key, 8) + item.registry);
            });
            info.push('');
            printMsg(info);
        });
    }
    function showCurrent() { //展示当前使用的镜像
        getCurrentRegistry(function(cur) { 
            var allRegistries = getAllRegistry();
            Object.keys(allRegistries).forEach(function(key) { 
                var item = allRegistries[key];
                if (item.registry === cur) {
                    printMsg([key]);
                    return;
                }
            });
        });
    }
    function onUse(name) { 
        var allRegistries = getAllRegistry();
        if (allRegistries.hasOwnProperty(name)) {
            var registry = allRegistries[name];
            npm.load(function (err) { 
                if (err) return exit(err);
                npm.commands.config(['set', 'registry', registry.registry], function (err, data) { 
                    if (err) return exit(err);
                    console.log(' ');
                    var newR = npm.config.get('registry');
                    printMsg([
                        '', ' Registry has been set to: ' + newR, ''
                    ]);
                })
            });
        } else {
            printMsg([
                '', ' Not find registry: ' + name, ''
            ]);
        }
    }
    function onDel(name) { 
        var customRegistries = getCustomRegistry();
        if (!customRegistries.hasOwnProperty(name)) return;
        getCurrentRegistry(function(cur) { 
            if (cur === customRegistries[name].registry) {
                onUse('npm');
            }
            delete customRegistries[name];
            setCustomRegistry(customRegistries, function(err) { 
                if (err) return exit(err);
                printMsg([
                    '', ' delete registry ' + name + ' success', ''
                ]);
            });
        });
    }
    function onAdd(name, url, home) { 
        var customRegistries = getCustomRegistry();
        if (customRegistries.hasOwnProperty(name)) return;
        var config = customRegistries[name] = {};
        if (url[url.length - 1] !== '/') url += '/'; // ensure url end with /
        config.registry = url;
        if (home) {
            config.home = home;
        }
        setCustomRegistry(customRegistries, function(err) { 
            if (err) return exit(err);
            printMsg([
                '', ' add registry ' + name + ' success', ''
            ]);
        });
    }
    function onHome(name, browser) { 
        var allRegistries = getAllRegistry();
        var home = allRegistries[name] && allRegistries[name].home;
        if (home) {
            var args = [home];
            if (browser) args.push(browser);
            open.apply(null, args);
        }
    }
    function onTest(registry) { 
        var allRegistries = getAllRegistry();
        var toTest;
        if (registry) {
            if (!allRegistries.hasOwnProperty(registry)) {
                return;
            }
            toTest = only(allRegistries, registry);
        } else {
            toTest = allRegistries;
        }
    
        async.map(Object.keys(toTest), function(name, cbk) { 
            var registry = toTest[name];
            var start = +new Date();
            request(registry.registry + 'pedding', function(error) { 
                cbk(null, {
                    name: name,
                    registry: registry.registry,
                    time: (+new Date() - start),
                    error: error ? true : false
                });
            });
        }, function(err, results) { 
            getCurrentRegistry(function(cur) { 
                var msg = [''];
                results.forEach(function(result) { 
                    var prefix = result.registry === cur ? '* ' : ' ';
                    var suffix = result.error ? 'Fetch Error' : result.time + 'ms';
                    msg.push(prefix + result.name + line(result.name, 8) + suffix);
                });
                msg.push('');
                printMsg(msg);
            });
        });
    }

###### 帮助信息方法 ######

/* helper methods /*/
    /* * get current registry */
    function getCurrentRegistry(cbk) { 
        npm.load(function(err, conf) { 
            if (err) return exit(err);
            cbk(npm.config.get('registry'));
        });
    }
    function getCustomRegistry() { 
        return fs.existsSync(NRMRC) ? ini.parse(fs.readFileSync(NRMRC, 'utf-8')) : {};
    }
    function setCustomRegistry(config, cbk) { 
        echo(ini.stringify(config), '>', NRMRC, cbk);
    }
    function getAllRegistry() { 
        return extend({}, registries, getCustomRegistry());
    }
    function printErr(err) { 
        console.error('an error occured: ' + err);
    }
    function printMsg(infos) { 
        infos.forEach(function(info) { 
            console.log(info);
        });
    }

###### 打印信息语句 ######

/* * print message & exit */
    function exit(err) { 
        printErr(err);
        process.exit(1);
    }
    function line(str, len) { 
        var line = new Array(Math.max(1, len - str.length)).join('-');
        return ' ' + line + ' ';
    }

3.registries.json文件说明  
在下面这个文件中，指明了镜像的地址，通过在.npmrc中修改该地址，能够进行切换npm镜像地址，下面就是可以拉取包的npm

{
        "npm": { "home": "https://www.npmjs.org", "registry": "https://registry.npmjs.org/" },
        "cnpm": { "home": "http://cnpmjs.org", "registry": "http://r.cnpmjs.org/" },
        "taobao": { "home": "https://npm.taobao.org", "registry": "https://registry.npm.taobao.org/" },
        "nj": { "home": "https://www.nodejitsu.com", "registry": "https://registry.nodejitsu.com/" },
        "rednpm": { "home": "http://npm.mirror.cqupt.edu.cn/", "registry": "http://registry.mirror.cqupt.edu.cn/" },
        "npmMirror": { "home": "https://skimdb.npmjs.com/", "registry": "https://skimdb.npmjs.com/registry/" },
        "edunpm": { "home": "http://www.enpmjs.org", "registry": "http://registry.enpmjs.org/" } }

#### 二、npm包发布问题 ####

[npm发布包–所遇到的问题][npm]

[npm_nrm-github]: https://github.com/Pana/nrm
[npm_nrm]: http://www.cnblogs.com/songqingbo/articles/5611588.html
[nrm]: /images/20220527/4f97995257654e7980232a826b7ca62a.png
[npm]: https://www.cnblogs.com/zuojiayi/p/6893330.html