This guide is designed to teach people how to use ChatGPT using a basic "I want one response" in PHP. This code is used in my travel itinerary generation website ReisPlan and built off my C# tutorial. I love how PHP handles JSON and XML data, so this tutorial is a bit easier.
Declare your API key (insert your OpenAI API key in the quotes)
// API endpoint URL
$url = 'https://api.openai.com/v1/chat/completions';
// Your OpenAI API key
$apiKey = '[API KEY]';The following code creates the JSON request to OpenAI. You can review all the options you can include here: https://platform.openai.com/docs/api-reference/chat/create.
It's worth noting that only the "model" and the "messages" are required in the body. There are many models, but I'm using gpt-3.5-turbo in this example. Likewise, there are a few roles you can use such as system, user, assistance, or function. Typically, the system role defines what you want to accomplish. In our example, we'll tell ChatGPT sytem role that is acting as a travel agent (used on my ReisPlan site).
First, we prepare the prompt statement:
// Prompt for the conversation
$messages = array(
array('role' => 'system', 'content' => 'You are a travel advisor that will deliver a detailed itinerary based on the information provided by the user.'),
array('role' => 'user', 'content' => 'I am traveling to Denver for 7 days. Things I\'m interested in include museums and hiking.')
);Next, we build a JSON array. In the below scenario, I'm only sending the prompt and the model using an array and then encoding it into JSON data using the json_encode function.
// Convert messages to JSON
$postData = array(
'messages' => $messages,
'model' => 'gpt-3.5-turbo' // Specify the model here
);
$jsonData = json_encode($postData);Next, we set up the headers using an array to send the request using the Authorization header with our API Key and JSON content type. The $options array will set up the header, method (POST), and content using the $jsonData we built above.
// Set headers for the API request
$headers = array(
'Content-Type: application/json',
'Authorization: Bearer ' . $apiKey
);
$options = array(
'http' => array(
'header' => implode("\r\n", $headers),
'method' => 'POST',
'content' => $jsonData
)
);The stream_context_create function will create the send data to OpenAI using an HTTP request.
$context = stream_context_create($options);Finally, we'll execute the API request using file_get_contents function and check for errors.
// Execute the API request
$response = file_get_contents($url, false, $context);
// Check for errors
if ($response === false) {
$error = error_get_last()['message'];
echo 'API request failed: ' . $error;
exit;
}We'll just the json_decode function to read the $response variable from OpenAI.
// Decode the API response
$data = json_decode($response, true);You will receive a JSON response like this in the $data variable (don't copy this):
{
"id": "chatcmpl-123",
"object": "chat.completion",
"created": 1677652288,
"model": "gpt-3.5-turbo-0613",
"choices": [{
"index": 0,
"message": {
"role": "assistant",
"content": "\n\nSure, I can recommend you check out Livin the Dream brewery in Littleton and Denver Beer Co in Englewood.",
},
"finish_reason": "stop"
}],
"usage": {
"prompt_tokens": 9,
"completion_tokens": 12,
"total_tokens": 21
}
}- choices[0] is the first response
- message is the node within the choices[0]
- content is the response you're looking for
Next, we'll extract the $data using the above and then explode individual lines in the response. The $reply variable contains the whole response.
But, I used $lines to break the reply response so I could get multiple lines of data and have them display on the website.
// Extract the assistant's reply
$reply = $data['choices'][0]['message']['content'];
// Output the reply
// Assuming $reply contains the response from the API
$lines = explode("\n", $reply);The following loop examines each $line received and displays it on the website using the echo function.
// Loop through the lines
$previousLineEmpty = false;
foreach ($lines as $line) {
// Process each line as needed
if (empty($line)) {
$previousLineEmpty = true;
} else {
if ($previousLineEmpty) {
echo "<br><strong>" . $line . "</strong><br>"; // Output the line in bold
$previousLineEmpty = false;
} else {
echo $line . "<br>"; // Output each line
}
}
}Now, put it together in all its glory:
// API endpoint URL
$url = 'https://api.openai.com/v1/chat/completions';
// Your OpenAI API key
$apiKey = '[API KEY]';
// Prompt for the conversation
$messages = array(
array('role' => 'system', 'content' => 'You are a travel advisor that will deliver a detailed itinerary based on the information provided the user.'),
array('role' => 'user', 'content' => 'I am traveling to Denver for 7. Things I\'m interested in include breweries.')
);
// Convert messages to JSON
$postData = array(
'messages' => $messages,
'model' => 'gpt-3.5-turbo' // Specify the model here
);
$jsonData = json_encode($postData);
// Set headers for the API request
$headers = array(
'Content-Type: application/json',
'Authorization: Bearer ' . $apiKey
);
$options = array(
'http' => array(
'header' => implode("\r\n", $headers),
'method' => 'POST',
'content' => $jsonData
)
);
$context = stream_context_create($options);
// Execute the API request
$response = file_get_contents($url, false, $context);
// Check for errors
if ($response === false) {
$error = error_get_last()['message'];
echo 'API request failed: ' . $error;
exit;
}
// Decode the API response
$data = json_decode($response, true);
// Extract the assistant's reply
$reply = $data['choices'][0]['message']['content'];Sure, I can recommend you check out Livin the Dream brewery in Littleton and Denver Beer Co in Englewood.