Der Aufbau einer Website von Grund auf neu Teil IX:. Abfragen von Daten mit SQL.
Was wir tun werden
In diesem Kapitel werden wir:
- Erstellen Sie Serverseiten
Server mit PHP und MySQL
<?php
header("Access-Control-Allow-Origin: *");
header("Content-Type:
application/json; charset=UTF-8");
$conn =
new mysqli("myServer", "myUser", "myPassword", "Northwind");
$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"] . '"}';
}
$outp ='{"records":['.$outp.']}';
$conn->close();
echo($outp);
?>Cross-Site HTTP-Requests
Anträge auf Daten von einem anderen Server (als der anfordernden Seite), sind Cross-Site - HTTP - Anforderungen genannt.
Cross-Site-Anforderungen sind sehr häufig im Internet.Many pages load css, images, or scripts from different servers. Viele Seiten laden CSS, Bilder oder Skripte von verschiedenen Servern.
In modernen Browsern, sind Cross-Site - HTTP - Anfragen von Skripten zu demselben Standort aus Sicherheitsgründen eingeschränkt.
Die folgende Zeile, in der PHP-Beispiel oben wurde hinzugefügt Zugriff auf die Seite von einem Cross-Site zu ermöglichen.
header("Access-Control-Allow-Origin: *");Server mit PHP und 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=Northwind.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();
}
$outp ='{"records":['.$outp.']}';
$conn->close();
echo ($outp);
?>Server Ausführen von ASP.NET, VB und 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=Northwind.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 & "records" & c & ":[" & outp & "]}"
conn.close
response.write(outp)
%>Server Ausführen von ASP.NET, Razor und SQL Lite
@{
Response.AppendHeader("Access-Control-Allow-Origin", "*")
Response.AppendHeader("Content-type",
"application/json")
var db =
Database.Open("Northwind");
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
+ "records" + c + ":[" + outp + "]}"
@outp