W3.JS 資料伺服器
動態資料
上一章中使用的都是從伺服器獲取的靜態資料。
用於從資料庫獲取動態資料的伺服器程式碼可以用多種不同的語言編寫。
以下是一些示例
執行 PHP 和 MySQL 的伺服器
<?php
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=UTF-8");
$conn = new mysqli("myServer", "user", "pass", "myDB");
$result = $conn->query("SELECT CompanyName, City, Country FROM Customers");
$outp = "";
while($rs = $result->fetch_array(MYSQLI_ASSOC)) {
if ($outp != "") {$outp .= ",";}
$outp .= '{"Name":"' . $rs["CompanyName"] . '",';
$outp .= '"City":"' . $rs["City"] . '",';
$outp .= '"Country":"'. $rs["Country"] . '"}';
}
$outp ='{"customers":['.$outp.']}';
$conn->close();
echo($outp);
?>
跨站點 HTTP 請求
從與請求頁面不同的伺服器請求資料，稱為跨站點 HTTP 請求。
跨站點請求在 Web 上很常見。許多頁面從不同伺服器載入 CSS、圖片或指令碼。
但是，在現代瀏覽器中，出於安全原因，來自指令碼的 HTTP 請求被限制在同一站點。
以下行（在上面的 PHP 示例中）允許從跨站點訪問頁面
header("Access-Control-Allow-Origin: *");
執行 Node.js 和 MySQL 的伺服器
var express = require('express');
var app = express();
app.get('/', function (req, res) {
var sql = require("mssql");
var config = {user:'user', password:'pass', server:'myServer', database:'myDB'};
sql.connect(config, function (err) {
if (err) console.log(err);
var request = new sql.Request();
request.query('SELECT CompanyName, City, Country FROM Customers', function (err, recordset) {
if (err) console.log(err)
res.send(recordset);
});
});
});
var server = app.listen(5000, function () {
console.log('Server is running..');
});
執行 ASP.NET、Razor 和 SQL Lite 的伺服器
@{
Response.AppendHeader("Access-Control-Allow-Origin", "*")
Response.AppendHeader("Content-type", "application/json")
var db = Database.Open("myDB");
var query = db.Query("SELECT CompanyName, City, Country FROM Customers");
var outp =""
var c = chr(34)
}
@foreach(var row in query)
{
if outp <> "" then outp = outp + ","
outp = outp + "{" + c + "Name" + c + ":" + c + @row.CompanyName + c + ","
outp = outp + c + "City" + c + ":" + c + @row.City + c + ","
outp = outp + c + "Country" + c + ":" + c + @row.Country + c + "}"
}
outp ="{" + c + "customers" + c + ":[" + outp + "]}"
@outp
執行 PHP 和 MS Access 的伺服器
<?php
header("Access-Control-Allow-Origin: *");
header("Content-Type: application/json; charset=ISO-8859-1");
$conn = new COM("ADODB.Connection");
$conn->open("PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source=myDB.mdb");
$rs = $conn->execute("SELECT CompanyName, City, Country FROM Customers");
$outp = "";
while (!$rs->EOF) {
if ($outp != "") {$outp .= ",";}
$outp .= '{"Name":"' . $rs["CompanyName"] . '",';
$outp .= '"City":"' . $rs["City"] . '",';
$outp .= '"Country":"'. $rs["Country"] . '"}';
$rs->MoveNext();
}
$outp ='{"customers":['.$outp.']}';
$conn->close();
echo ($outp);
?>
執行 ASP.NET、VB 和 MS Access 的伺服器
<%@ Import Namespace="System.IO"%>
<%@ Import Namespace="System.Data"%>
<%@ Import Namespace="System.Data.OleDb"%>
<%
Response.AppendHeader("Access-Control-Allow-Origin", "*")
Response.AppendHeader("Content-type", "application/json")
Dim conn As OleDbConnection
Dim objAdapter As OleDbDataAdapter
Dim objTable As DataTable
Dim objRow As DataRow
Dim objDataSet As New DataSet()
Dim outp
Dim c
conn = New OledbConnection("Provider=Microsoft.Jet.OLEDB.4.0;data source=myDB.mdb")
objAdapter = New OledbDataAdapter("SELECT CompanyName, City, Country FROM Customers", conn)
objAdapter.Fill(objDataSet, "myTable")
objTable=objDataSet.Tables("myTable")
outp = ""
c = chr(34)
for each x in objTable.Rows
if outp <> "" then outp = outp & ","
outp = outp & "{" & c & "Name" & c & ":" & c & x("CompanyName") & c & ","
outp = outp & c & "City" & c & ":" & c & x("City") & c & ","
outp = outp & c & "Country" & c & ":" & c & x("Country") & c & "}"
next
outp ="{" & c & "customers" & c & ":[" & outp & "]}"
conn.close
response.write(outp)
%>
