數據從服務器
在前面的章節中使用的數據是從服務器中提取。
一種用於從數據庫中獲取動態數據的服務器代碼可以寫在許多不同的語言。
這裡有些例子：
服務器運行PHP和MySQL
<?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
從不同的服務器請求數據（而不是請求頁），被稱為跨站點的HTTP請求。
跨站點請求是在網絡上非常普遍。 許多網頁加載CSS，圖像或腳本來自不同的服務器。
在現代瀏覽器， 從腳本跨站點的HTTP請求被限制在同一站點出於安全原因。
以下行（在上面的PHP的例子）可以被添加到允許訪問從跨網站的網頁：
header("Access-Control-Allow-Origin: *");服務器運行的Node.js和MySQL
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..');
});服務器運行ASP.NET，剃刀和SQL精簡版
@{
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
服務器運行PHP和MS Access
<?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);
?>服務器運行ASP.NET，VB和MS Access
<%@ 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)
%>