我有使用PHP完成的这项挑战,但希望了解如何通过node.js和SQL完成。
我是这个的初学者,并且根本不确定我甚至做了什么是合法的,但我想学习在节点中做到这一点;挑战是:
我们想要一个将浏览器的UserAgent作为字符串接收的函数,并将其与已批准的浏览器和版本列表进行比较
数据库结构看起来如下:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| bigIntPKID | varchar(50)BrowserName | varchar(50)VersionNumber | bitGreaterVersions |
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 1 | Internet Explorer | 9 |假|
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 1 | Internet Explorer | 10 |假|
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 1 | Chrome | 26 |真的|
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 1 | Firefox | 22 |真的|
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bitGreaterVersions是大于版本号兼容的任何版本。
以人类可读格式表示的数据表将是“我们的应用程序与IE9,10,Chrome 26+和Firefox 22+兼容”
创建一个将用户代理作为字符串的函数,如果它基于上述条件兼容,则返回true或false。
然后这是节点和SQL代码(我希望)......
var express = require("express");
var mysql = require("mysql");
var connection = mysql.createConnection({
host: 'localhost',
username: 'username',
password: 'password',
dbname: 'browsers'
});
var app = express();
// if there is an error connecting to the database
connection.connect(function(error) {
if(error) {
console.log('Cannot establish connection to database...');
return;
}
console.log('Database connection established...');
});
// function to check browser compatibility
function getUserAgent(userAgent, versionNumber) {
var isBrowserCompatible;
// access the database
app.get("/path-to-database", function(req, res) {
// query for the required results
connection.query('SELECT BrowserName, VersionNumber, bitGreaterVersions FROM userAgentTable', function(error, rows, fields) {
connection.end();
if(error) {
console.log('Cannot find the results...');
}
isBrowserCompatible = false;
// loop over the returned table values
for(var i = 0; i < rows.length; i++) {
// if browser name and version number are equal to userAgent and versionNumber
if(rows[i].BrowserName == userAgent && rows[i].VersionNumber == versionNumber) {
// the browser is compatible
isBrowserCompatible = true;
break;
// if browser name is equal to userAgent but the version number is less than versionNumber
} else if(rows[i].BrowserName == userAgent && rows[i].VersionNumber < versionNumber) {
if(rows[i].bitGreaterVersions == 'False') {
// the browser is not compatible
break;
} else {
// otherwise the browser is compatible
isBrowserCompatible = true;
break;
}
}
}
return isBrowserCompatible;
});
});
return isBrowserCompatible;
}
希望有人可以指出我正确的方向。我主要是想看看实际功能是否可以按照我拥有它的方式合法编写,如果没有,如何去做,逻辑和所有。要温柔......
答案 0 :(得分:1)
您可以使用ua-parser-js包来解析用户代理字符串。
var parser = require("ua-parser-js");
// somewhere within the server request-response cycle
// you get user-agent header
var ua = parser(req.headers["user-agent"]);
// ua.getBrowser() returns an object with the browser name and version
var details = ua.getBrowser();
// e.g. returns { name: "Chrome", version: "52.0.2743.116" }
// details.version.split(".") will return an array of strings
// ["52", "0", "2743", "116"] you are only interest in the [0] element
var browser = details.name;
var version = parseInt(details.version.split(".")[0]); // 52
使用browser
和version
数据,您可以查询数据库。
// var mysql = require('mysql');
// etc. etc.
connection.query("SELECT * FROM BrowserTable WHERE BrowserName = ?", [browser],
function(error, rows) {
// handle error
if (error) {
throw error;
}
// process the results returned
var isCompatible = false;
for (var i = 0; i < rows[0].length; i++) {
var dbVersion = parseInt(rows[0][i].VersionNumber);
if ( ((rows[0][i].bitGreaterVersions == 'True') && (dbVersion < version))
|| (dbVersion == version) ) {
isCompatible = true;
break;
}
}
return isCompatible;
});