Natively Connect to NASA Data in PHP via ODBC (Linux)

Drop the CData API Driver for ODBC into your LAMP or WAMP stack to build NASA-connected Web applications. This article shows how to use PHP's ODBC built-in functions to connect to NASA data, execute queries, and output the results.

Using the CData ODBC Drivers on a UNIX/Linux Machine

The CData ODBC Drivers are supported in various Red Hat-based and Debian-based systems, including Ubuntu, Debian, RHEL, CentOS, and Fedora. There are also several libraries and packages that are required, many of which may be installed by default, depending on your system. For more information on the supported versions of Linux operating systems and the required libraries, please refer to the "Getting Started" section in the help documentation (installed and found online).

Installing the Driver Manager

Before installing the driver, check that your system has a driver manager. For this article, you will use unixODBC, a free and open source ODBC Driver manager that is widely supported.

For Debian-based systems like Ubuntu, you can install unixODBC with the APT package manager:

$ sudo apt-get install unixodbc unixodbc-dev

For systems based on Red Hat Linux, you can install unixODBC with yum or dnf:

$ sudo yum install unixODBC unixODBC-devel

The unixODBC driver manager reads information about drivers from an odbcinst.ini file and about data sources from an odbc.ini file. You can determine the location of the configuration files on your system by entering the following command into a terminal:

$ odbcinst -j

The output of the command will display the locations of the configuration files for ODBC data sources and registered ODBC drivers. User data sources can only be accessed by the user account whose home folder the odbc.ini is located in. System data sources can be accessed by all users. Below is an example of the output of this command:

DRIVERS............: /etc/odbcinst.ini
SYSTEM DATA SOURCES: /etc/odbc.ini
FILE DATA SOURCES..: /etc/ODBCDataSources
USER DATA SOURCES..: /home/myuser/.odbc.ini
SQLULEN Size.......: 8
SQLLEN Size........: 8
SQLSETPOSIROW Size.: 8

Installing the Driver

You can download the driver in standard package formats: the Debian .deb package format or the .rpm file format. Once you have downloaded the file, you can install the driver from the terminal.

The driver installer registers the driver with unixODBC and creates a system DSN, which can be used later in any tools or applications that support ODBC connectivity.

For Debian-based systems like Ubuntu, run the following command with sudo or as root:

$ dpkg -i /path/to/package.deb

For Red Hat systems or other systems that support .rpms, run the following command with sudo or as root:

$ rpm -i /path/to/package.rpm

Once the driver is installed, you can list the registered drivers and defined data sources using the unixODBC driver manager:

List the Registered Driver(s)

$ odbcinst -q -d
CData API Driver for ODBC
...

List the Defined Data Source(s)

$ odbcinst -q -s
CData API Source
...

To use the CData API Driver for ODBC with unixODBC, ensure that the driver is configured to use UTF-16. To do so, edit the INI file for the driver (cdata.odbc.api.ini), which can be found in the lib folder in the installation location (typically /opt/cdata/cdata-odbc-driver-for-api), as follows:

cdata.odbc.api.ini

...

[Driver]
DriverManagerEncoding = UTF-16

Modifying the DSN

The driver installation predefines a system DSN. You can modify the DSN by editing the system data sources file (/etc/odbc.ini) and defining the required connection properties. Additionally, you can create user-specific DSNs that will not require root access to modify in $HOME/.odbc.ini.

Using API Key Authentication

Most NASA API endpoints (APOD, NeoWS, DONKI, TechTransfer) require a NASA API key. Register for a free key at https://api.nasa.gov. The default DEMO_KEY provides limited access (30 requests/hour, 50 requests/day); a registered key allows 1,000 requests/hour.

The following endpoints do not require an API key and work without authentication: EONET (Earth Observatory Natural Event Tracker), EPIC (Earth Polychromatic Imaging Camera), NASA Image and Video Library, and TechPort.

After obtaining your API key, set the following connection properties:

• AuthScheme: Set this to APIKey.
• APIKey: Set this to your NASA API key. Use DEMO_KEY for limited testing.

Example Connection String

Profile=C:\profiles\NASA.apip;AuthScheme=APIKey;APIKey=YOUR_NASA_API_KEY

Connecting to NASA

Once the authentication is configured, you can connect to NASA and query data from any of the available tables such as AstronomyPictureOfDay, NearEarthObjectFeed, EonetEvents, and NasaImageLibrary.

/etc/odbc.ini or $HOME/.odbc.ini

[CData API Source]
Driver = CData API Driver for ODBC
Description = My Description
Profile = C:\profiles\NASA.apip
AuthScheme = APIKey
APIKey = YOUR_NASA_API_KEY

For specific information on using these configuration files, please refer to the help documentation (installed and found online).

Establish a Connection

Open the connection to NASA by calling the odbc_connect or odbc_pconnect methods. To close connections, use odbc_close or odbc_close_all.

$conn = odbc_connect("CData ODBC API Source","user","password");

Connections opened with odbc_connect are closed when the script ends. Connections opened with the odbc_pconnect method are still open after the script ends. This enables other scripts to share that connection when they connect with the same credentials. By sharing connections among your scripts, you can save system resources and queries execute faster.

$conn = odbc_pconnect("CData ODBC API Source","user","password");
...
odbc_close($conn); //persistent connection must be closed explicitly

Create Prepared Statements

Create prepared statements and parameterized queries with the odbc_prepare function.

$query = odbc_prepare($conn, "SELECT * FROM AstronomyPictureOfDay WHERE StartDate = ?");

Execute Queries

Execute prepared statements with odbc_execute.

$conn = odbc_connect("CData ODBC API Source","user","password");
$query = odbc_prepare($conn, "SELECT * FROM AstronomyPictureOfDay WHERE StartDate = ?");
$success = odbc_execute($query, array('2024-01-01'));
  

Execute nonparameterized queries with odbc_exec.

$conn = odbc_connect("CData ODBC API Source","user","password");
$query = odbc_exec($conn, "SELECT ,  FROM AstronomyPictureOfDay WHERE StartDate = '2024-01-01'");
  

Process Results

Access a row in the result set as an array with the odbc_fetch_array function.

$conn = odbc_connect("CData ODBC NASA data Source","user","password");
$query = odbc_exec($conn, "SELECT ,  FROM AstronomyPictureOfDay WHERE StartDate = '2024-01-01'");
while($row = odbc_fetch_array($query)){
 echo $row[""] . "\n";
}

Display the result set in an HTML table with the odbc_result_all function.

$conn = odbc_connect("CData ODBC NASA data Source","user","password");
$query = odbc_prepare($conn, "SELECT * FROM AstronomyPictureOfDay WHERE StartDate = ?");
$success = odbc_execute($query, array('2024-01-01'));
if($success)
  odbc_result_all($query);

More Example Queries

You will find complete information on the SQL queries supported by the driver in the help documentation. The code examples above are NASA-specific adaptations of the PHP community documentation for all ODBC functions.