Php read email & attachments from google using oauth

You can get access token & other details to perform this action:
http://pritomkumar.blogspot.com/2016/11/using-oauth-20-for-google-client-side.html

Code snippet to read email & attachments from google using oauth

<?php
session_start();
init();
if(isset($_GET["email_id"])) {
    email_details();
}
else if(isset($_GET["email_attachment"])) {
    email_attachment();
}
else {
    list_email();
}

function init() {
    $_SESSION["google_user_id"] = "11822454346345607576118";
    $_SESSION["access_token"] = "ya29.CjCgA8bf_BCrsdfsdfsdfsdf5orH3cvbMMzQY0RX8NUrbgpNhm9oXHyAAZ0WF3Jid4WwQ";

    /* Permissions to read email */
    $_SESSION["scope"] = "https://www.googleapis.com/auth/userinfo.profile"; /* User profile */
    $_SESSION["scope"] .= " https://www.googleapis.com/auth/gmail.readonly"; /* Read mail */
}

function email_attachment() {
    $id = $_GET["email_attachment"];
    $name = $_GET["name"];
    if (!file_exists("attachments")) {
        mkdir("attachments");
    }

    $apiUrl = "https://www.googleapis.com/gmail/v1/users/".$_SESSION["google_user_id"];
    $apiUrl .= "/messages/$id/attachments/".$id;
    $apiUrl .= "?access_token=".$_SESSION["access_token"];
    $remoteFile = decode_content(json_decode(make_request($apiUrl))->data);
    $file = "attachments/".md5(time()).$name;
    file_put_contents($file, $remoteFile);
    header("Location: $file");
    exit;
}

function email_details() {
    $id = $_GET["email_id"];
    $raw = "";// "format=raw&";
    $fields = "";// "fields=raw&";
    $apiUrl = "https://www.googleapis.com/gmail/v1/users/";
    $apiUrl .= $_SESSION["google_user_id"]."/messages/$id?$raw$fields";
    $apiUrl .= "access_token=".$_SESSION["access_token"];
    //echo $apiUrl; die();
    $result = json_decode(make_request($apiUrl));
    //file_put_contents("raw-email.txt", $result->raw); die();
    //echo "<pre>"; print_r($result); echo "</pre>"; die();

    $message = parse_email($result->payload->parts);
    $link = ""; $html = "";
    foreach($message as $msg) {
        if($msg["type"] == "html") {
            $html = $msg["body"];
        }
        else if($msg["type"] == "text") {
            //you can do anything with text part of email
        }
        else {
            $link .= "<a href='?email_attachment=".$msg["body"]."&name=".$msg["name"]."' target='_blank'>".$msg["name"]."</a><br/>";
        }
    }
    echo "<h3><i>Email Attachments:</i></h3>".$link."<h3><i>Email Body:</i></h3>".trim($html);
}

function parse_email($email) {
    $result = array();
    for($i = 0; $i < count($email); $i++) {
        $part = $email[$i];
        $mime = $part->mimeType;
        $name = $part->filename;
        if(strlen($name) > 0) {
            $file = array();
            $file["type"] = $mime;
            $file["name"] = $name;
            $file["body"] = $part->body->attachmentId;
            array_push($result, $file);
        }
        else if($mime === "text/plain") {
            $file = array();
            $file["type"] = "text";
            $file["name"] = "email_body_plain.html";
            $file["body"] = decode_content($part->body->data);
            array_push($result, $file);
        }
        else if($mime === "text/html") {
            $file = array();
            $file["type"] = "html";
            $file["name"] = "email_body_html.html";
            $file["body"] = decode_content($part->body->data);
            array_push($result, $file);
        }
        else if(substr($mime, 0, 9) === "multipart") {
            foreach(parse_email($part->parts) as $file) {
                array_push($result, $file);
            }
        }
    }
    return $result;
}

function decode_content($content) {
    return base64_decode(str_replace("-", "+", str_replace("_", "/", $content)));
}

function list_email() {
    //gmail api ref page: https://developers.google.com/gmail/api/v1/reference/
    //https://developers.google.com/gmail/api/v1/reference/users/messages/list
    //Searching filtering gmail over oauth2 api using php
    //https://developers.google.com/gmail/api/guides/filtering
    //https://support.google.com/mail/answer/7190?hl=en

    $search = "from:pritom@xxx.com OR from:pritomkucse@gmail.com"; //Search by from address
    $search = "subject:Fwd:"; //Words in the subject line
    $search = "label:sent OR label:starred"; //With certain labels
    $search = "has:attachment"; //Any email with attachments
    $search = "is:important"; //Important mails only
    $search = "is:read"; //For mails those are read already
    $search = "is:unread"; //For mails those are not read yet
    $search = "cc:pritomkucse@gmail.com"; //Emails has specific cc, bcc not allowed
    $search = "after:2016/11/19 AND label:inbox"; //Emails reached inbox after specific date
    $search = "before:2016/04/19 AND label:inbox"; //Emails reached inbox before specific date
    $search = "has:nouserlabels"; //Emails with no labels
    $search = "deliveredto:pritom@xxx.com"; //Emails delivered to some address
    $search = "size:10000"; //Email larger than bytes
    $search = "larger:15M"; //Emails larger than megabytes
    $search = "smaller:1M"; //Emails smaller than megabytes
    $search = "newer_than:1d"; //Emails newer than 1 day (d/m/y)
    $search = "older_than:20d"; //Emails older than 1 day (d/m/y)
    $search = "category:updates"; //Emails in specific category
    $search = "rfc822msgid:2021140448.450273.1479617087520.JavaMail.zimbra@bitmascot.com"; //Specific message by Message-ID
    $search = "!from:@gmail.com"; //Search by not from domain
    $search = "!from:pritomkucse@google.com"; //Search by not from address
    $search = ""; //No filtering

    $maxResults = 10;
    $apiUrl = "https://www.googleapis.com/gmail/v1/users/".$_SESSION["google_user_id"]."/messages?";
    $apiUrl .= "access_token=".$_SESSION["access_token"];
    $apiUrl .= "&maxResults=".$maxResults;
    if(strlen($search) > 0) {
        $apiUrl .= "&q=" . urlencode($search);
    }
    if(isset($_GET["next_page"]) && strlen($_GET["next_page"]) > 0) {
        $apiUrl .= "&pageToken=". $_GET["next_page"];
    }
    $result = json_decode(make_request($apiUrl));
    //echo "<pre>";print_r($result);echo "</pre>";die();

    if(isset($result->messages)) {
        foreach($result->messages as $m) {
            $link = "<a target='_blank' href='?email_id=".$m->id."'>View Message [[".$m->id . "]]</a><br/>";
            echo $link;
        }
    }
    else {
        echo "<pre>"; print_r($result); echo "</pre>"; die();
    }
    if(isset($result->nextPageToken)) {
        echo "<a href='?email=true&next_page=".$result->nextPageToken."'>Next_Page</a>";
    }
}

function make_request($url, $post = null, $headers = null, $returnArray = false) {
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_URL, $url);
    curl_setopt($curl, CURLOPT_POST, $post == null ? 0 : 1);
    if($post != null) {
        curl_setopt($curl, CURLOPT_POSTFIELDS, $post);
    }
    curl_setopt($curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($curl, CURLOPT_SSLVERSION, 1);
    if($headers != null) {
        curl_setopt($curl, CURLOPT_HEADER, true);
        curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
    }
    $response = curl_exec($curl);
    $http_code = curl_getinfo($curl, CURLINFO_HTTP_CODE);
    $header_size = curl_getinfo($curl, CURLINFO_HEADER_SIZE);
    curl_close($curl);
    if($http_code >= 400) {
        echo "Error executing request to Office365 api with error code=$http_code<br/><br/>\n\n";
        echo "<pre>"; print_r($response); echo "</pre>";
        die();
    }
    if($returnArray) {
        return array(
            "response" => $response,
            "header_size" => $header_size
        );
    }
    return $response;
}
?>