Query Presto Data Using the OData SDK for PHP

The CData API Server, when paired with the ADO.NET Provider for Presto, exposes Presto data (or data from any of 200+ other ADO.NET Providers) as Web services. You can follow the procedure below to work with Presto data as PHP objects.

Getting Started

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Set Up the API Server

Follow the steps below to begin producing secure Presto OData services:

Deploy

The API Server runs on your own server. On Windows, you can deploy using the stand-alone server or IIS. On a Java servlet container, drop in the API Server WAR file. See the help documentation for more information and how-tos.

The API Server is also easy to deploy on Microsoft Azure, Amazon EC2, and Heroku.

Connect to Presto

After you deploy the API Server and the ADO.NET Provider for Presto, provide authentication values and other connection properties needed to connect to Presto by clicking Settings -> Connections and adding a new connection in the API Server administration console.

Set the Server and Port connection properties to connect, in addition to any authentication properties that may be required.

To enable TLS/SSL, set UseSSL to true.

Authenticating with LDAP

In order to authenticate with LDAP, set the following connection properties:

• AuthScheme: Set this to LDAP.
• User: The username being authenticated with in LDAP.
• Password: The password associated with the User you are authenticating against LDAP with.

Authenticating with Kerberos

In order to authenticate with KERBEROS, set the following connection properties:

• AuthScheme: Set this to KERBEROS.
• KerberosKDC: The Kerberos Key Distribution Center (KDC) service used to authenticate the user.
• KerberosRealm: The Kerberos Realm used to authenticate the user with.
• KerberosSPN: The Service Principal Name for the Kerberos Domain Controller.
• KerberosKeytabFile: The Keytab file containing your pairs of Kerberos principals and encrypted keys.
• User: The user who is authenticating to Kerberos.
• Password: The password used to authenticate to Kerberos.

You can then choose the Presto entities you want to allow the API Server access to by clicking Settings -> Resources.

Additionally, configure the API Server for compatibility with the OData SDK for PHP: Click Server -> Settings and in the OData section set Default Version to 2.0.

Authorize API Server Users

After determining the OData services you want to produce, authorize users by clicking Settings -> Users. The API Server uses authtoken-based authentication and supports the major authentication schemes. You can authenticate as well as encrypt connections with SSL. Access can also be restricted based on IP address; by default, only connections from the local machine are allowed.

For simplicity, we will authenticate to the API Server by setting the authtoken in the URL. This is not enabled by default; you will need to add the following lines to the API Server configuration file, settings.cfg.

The settings.cfg file is located in the data directory. In the .NET edition, the data directory is the app_data folder under the www folder. In the Java edition, the data directory's location depends on the operation system:

• Windows: C:\ProgramData\CData\Presto\
• Unix or Mac OS X: ~/cdata/Presto/

Work with Presto Entities as PHP Objects

Follow the steps below to use the ODataPHP SDK to create a proxy class that will connect to the Web services exposed by the API Server.

1. Pass the URL to a command like the one below:

   php C:\PHPLib\ODataphp\PHPDataSvcUtil.php /uri=https://your-server:8032/api.rsc/@your-authtoken/ /out=C:\PHPLib\ODataphp\PrestoEntities.php

   The preceding command defines classes from the metadata returned in the response from the OData endpoint, then outputs the class definitions to the specified folder.

   Both the API Server and the OData SDK for PHP support forms and Windows authentication. The API Server uses authtokens to authenticate users authorized to access the OData endpoint. You can supply authtokens in HTTP Basic authentication or append them to the OData URL.

   You can configure authorized users in the Settings -> Users section of the API Server administration console.

2. You can now start accessing Presto data using an object-oriented interface in PHP. The code below creates a record of the Customer table and then retrieves the live data, showing the newly created record.

   require_once 'PrestoEntities.php'; try{ $svc = new CData(); $customer = new Customer(); $customer->Id = '123456789'; $svc->AddToCustomer($customer); $svc->SetSaveChangesOptions(SaveChangesOptions::None); $svc->SaveChanges(); $response = $svc->customer()->Execute(); foreach($response->Result as $customer) echo $customer->FirstName."
"; } catch (Exception $e) { //catch errors from the API Server echo $e->getError(), "\n"; }