PHP sample code for a multipart file upload to Backblaze B2. Usage: php php_multipart.php [-v] <bucket_name> <local_file>

b2_multipart.php

<?php

// PHP sample code to show multipart file upload using the B2 Native API

// User supplies optional -v for verbose output from curl, then bucket name 
// and path to local file
$rest_index = null;
$opts = getopt("v::", [], $rest_index);
$args = array_slice($argv, $rest_index);

$verbose = (count($opts) == 1);

if (count($args) != 2) {
    echo "Usage: $argv[0] [-v] <bucket_name> <local_file>\n";
    exit(1);
}

$bucket_name = $args[0];
$local_file = $args[1];

// Safest way to pass credentials is as environment variables
$application_key_id = getenv("B2_APPLICATION_KEY_ID");
$application_key = getenv("B2_APPLICATION_KEY");
if (!$application_key_id || !$application_key) {
    echo "You must set the B2_APPLICATION_KEY_ID and B2_APPLICATION_KEY environment variables";
    exit(2);
}

//
// First, call b2_authorize_account to get authorization token
//

// Basic auth for token request
$credentials = base64_encode("$application_key_id:$application_key");

$url = "https://api.backblazeb2.com/b2api/v2/b2_authorize_account";
$session = curl_init($url);

$headers = array(
    "Accept: application/json",
    "Authorization: Basic $credentials"
);

curl_setopt($session, CURLOPT_HTTPHEADER, $headers);
curl_setopt($session, CURLOPT_HTTPGET, true);
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
curl_setopt($session, CURLOPT_VERBOSE, $verbose);

echo "Calling b2_authorize_account... ";
$server_output = curl_exec($session);
$http_code = curl_getinfo($session, CURLINFO_HTTP_CODE);
curl_close ($session);

echo "status: $http_code \n";
echo "$server_output\n";

$auth_response = json_decode($server_output);

$account_id = $auth_response->accountId;
$api_url = $auth_response->apiUrl;
$auth_token = $auth_response->authorizationToken;

//
// Get the id from the bucket name
//

$session = curl_init($api_url .  "/b2api/v2/b2_list_buckets");

$data = array(
    "accountId" => $account_id,
    "bucketName" => $bucket_name
);

$headers = array(
    "Authorization: $auth_token"
);

curl_setopt($session, CURLOPT_HTTPHEADER, $headers); 
curl_setopt($session, CURLOPT_POSTFIELDS, json_encode($data)); 
curl_setopt($session, CURLOPT_POST, true);
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
curl_setopt($session, CURLOPT_VERBOSE, $verbose);

echo "Calling b2_list_buckets... ";
$server_output = curl_exec($session);
$http_code = curl_getinfo($session, CURLINFO_HTTP_CODE);
curl_close ($session);

echo "status: $http_code \n";
echo "$server_output\n";

$list_response = json_decode($server_output);

$bucket_id = $list_response->buckets[0]->bucketId;

//
// Set up the large file upload
//

$file_name = basename($local_file);
$content_type = "b2/x-auto";

$data = array(
    "fileName" => $file_name, 
    "bucketId" => $bucket_id, 
    "contentType" => $content_type
);

$headers = array(
    "Accept: application/json",
    "Authorization: $auth_token"
);

$session = curl_init("$api_url/b2api/v2/b2_start_large_file");

curl_setopt($session, CURLOPT_HTTPHEADER, $headers);
curl_setopt($session, CURLOPT_POSTFIELDS, json_encode($data)); 
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
curl_setopt($session, CURLOPT_VERBOSE, $verbose);

echo "Calling b2_start_large_file... ";
$server_output = curl_exec($session);
$http_code = curl_getinfo($session, CURLINFO_HTTP_CODE);
curl_close ($session);

echo "status: $http_code \n";
echo "$server_output\n";

$start_response = json_decode($server_output);

$file_id = $start_response->fileId;

// This sample uses the smallest permitted part size, 5 MB, to more easily show
// multipart uploads in action. The default part size is 100 MB
$part_size = 5 * 1000 * 1000;
$local_file_size = filesize($local_file);
$total_bytes_sent = 0;
$sha1_of_parts = array();
$part_no = 1;
$file_handle = fopen($local_file, "r");

// Loop through parts of file
//
// Note - for simplicity, this sample does not handle errors or implement the
// retry logic outlined at https://www.backblaze.com/b2/docs/uploading.html
//
// Production code should implement error handling and retry requests.
//
while ($total_bytes_sent < $local_file_size) {

    //
    // Get upload part URL
    //
    $data = array("fileId" => $file_id);

    $headers = array(
        "Accept: application/json",
        "Authorization: $auth_token"
    );

    $session = curl_init("$api_url/b2api/v2/b2_get_upload_part_url");
    curl_setopt($session, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($session, CURLOPT_POSTFIELDS, json_encode($data)); 
    curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($session, CURLOPT_VERBOSE, $verbose);

    echo "b2_get_upload_part_url...";
    $server_output = curl_exec($session);
    $http_code = curl_getinfo($session, CURLINFO_HTTP_CODE);
    curl_close ($session);

    echo "status: $http_code \n";
    echo "$server_output\n";

    $part_response = json_decode($server_output);

    $large_file_auth_token = $part_response->authorizationToken;
    $upload_url = $part_response->uploadUrl;

    $bytes_sent_for_part = min($local_file_size - $total_bytes_sent, $part_size);

    //
    // Upload the part to the URL we just received
    //

    // Get a sha1 of the part we are going to send  
    fseek($file_handle, $total_bytes_sent);
    $data_part = fread($file_handle, $bytes_sent_for_part);
    array_push($sha1_of_parts, sha1($data_part));
    fseek($file_handle, $total_bytes_sent);

    $session = curl_init($upload_url);

    // NOTE - we need to set a blank Transfer-Encoding header, otherwise PHP will
    // default to chunked transfer encoding and remove the content length header
    $headers = array(
        "Accept: application/json",
        "Authorization: $large_file_auth_token",
        "Transfer-Encoding:",
        "Content-Length: $bytes_sent_for_part",
        "X-Bz-Part-Number: $part_no",
        "X-Bz-Content-Sha1: {$sha1_of_parts[$part_no - 1]}"
    );

    curl_setopt($session, CURLOPT_POST, true);
    curl_setopt($session, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($session, CURLOPT_INFILE, $file_handle);
    curl_setopt($session, CURLOPT_INFILESIZE, (int)$bytes_sent_for_part);
    curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($session, CURLOPT_VERBOSE, $verbose);

    echo "Calling b2_upload_part with $bytes_sent_for_part bytes... ";
    $server_output = curl_exec($session);
    $http_code = curl_getinfo($session, CURLINFO_HTTP_CODE);
    curl_close ($session);
    echo "status: $http_code\n";
    echo "$server_output\n";

    $part_no++;
    $total_bytes_sent += $bytes_sent_for_part;
}
fclose($file_handle);

//
// Finish the upload
//

$session = curl_init("$api_url/b2api/v2/b2_finish_large_file");

$data = array(
    "fileId" => $file_id,
    "partSha1Array" => $sha1_of_parts
);

$headers = array(
    "Accept: application/json",
    "Authorization: $auth_token"
);

curl_setopt($session, CURLOPT_POSTFIELDS, json_encode($data)); 
curl_setopt($session, CURLOPT_HTTPHEADER, $headers);
curl_setopt($session, CURLOPT_RETURNTRANSFER, true);
curl_setopt($session, CURLOPT_VERBOSE, $verbose);

echo "b2_finish_large_file... ";
$server_output = curl_exec($session);
$http_code = curl_getinfo($session, CURLINFO_HTTP_CODE);
curl_close ($session);

echo "status: $http_code\n";
echo "$server_output\n";

?>