{"id":1010,"date":"2020-08-13T20:27:04","date_gmt":"2020-08-13T20:27:04","guid":{"rendered":"http:\/\/spiderwiz.org\/project\/?page_id=1010"},"modified":"2025-04-09T06:15:59","modified_gmt":"2025-04-09T06:15:59","slug":"lesson-16","status":"publish","type":"page","link":"https:\/\/spiderwiz.org\/project\/tutorial\/lesson-16\/","title":{"rendered":"Lesson 16: Writing a Mail Plugin"},"content":{"rendered":"\n

We saw in Lesson 13<\/a> that a Spiderwiz-based application can\nbe configured to automatically send notifications, alerts and exception reports\nby email. Currently Spiderwiz supports only SMTP mail, but other messaging\nsystems can be added by writing a custom Mail plugin. We will see an example\nhere.<\/p>\n\n\n\n

We are going to write a WhatsApp messaging plugin. Actually\nit will be a dual system plugin. If the address to send to is of the form\n\u201cwhatsapp:<phone number<\/em>>\u201d then\na WhatsApp message is sent, otherwise SMTP mail is used to send an email.<\/p>\n\n\n\n

Mail plugins need to implement the ZMail<\/a> interface. However since we want to revert\nto the standard SMTP mail when the addressee is not a WhatsApp account we will\nextend ZSMTPMail<\/a> that is by itself an implementation of ZMail<\/code>.<\/p>\n\n\n\n

Our implementation uses the Twilio SDK<\/a>. To use it, we need to include the\nfollowing dependency:<\/p>\n\n\n\n

<dependency>\n    <groupId>com.twilio.sdk<\/groupId>\n    <artifactId>twilio<\/artifactId>\n    <version>7.54.2<\/version>\n    <classifier>jar-with-dependencies<\/classifier>\n<\/dependency><\/pre><\/div>\n\n\n\n
With this in place, let\u2019s see WhatsAppMail<\/code>:<\/p>\n\n\n\n
package org.spiderwiz.tutorial.lesson16;\n\nimport com.twilio.Twilio;\nimport com.twilio.rest.api.v2010.account.Message;\nimport com.twilio.type.PhoneNumber;\nimport java.io.UnsupportedEncodingException;\nimport java.util.Map;\nimport javax.mail.MessagingException;\nimport org.spiderwiz.zutils.ZHtml;\nimport org.spiderwiz.zutils.ZSMTPMail;\n\n\/**\n * A class that extends ZSMTPMail to implement a dual mail system. If the addressee is a WhatsApp phone number then the message is\n * sent via WhatsApp, otherwise the 'super' methods are called to process SMTP mail.\n * otherwise \n *\/\npublic class WhatsAppMail extends ZSMTPMail {\n    private final static String WHATSAPP_PREFIX = "whatsapp:";\n    \n    private String sid;\n    private String auth;\n    private String fromNumber;\n\n    \/**\n     * Configure WhatsApp with a Twilio Account SID, Auth Token and the sender phone number,\n     * then call the super method to configure SMTP mail.\n     * @param configParams the configuration map.\n     *\/\n    @Override\n    public synchronized void configure(Map<String, String> configParams) {\n        sid = configParams.get("sid");\n        auth = configParams.get("auth");\n        fromNumber = configParams.get("from");\n        if (fromNumber != null)\n            fromNumber = WHATSAPP_PREFIX + fromNumber;\n        super.configure(configParams);\n    }\n    \n    @Override\n    public void send(String from, String to, String cc, String subject, String body, boolean html, boolean highPriority)\n        throws MessagingException, UnsupportedEncodingException\n    {\n        \/\/ Try first WhatsApp\n        boolean toWhatsApp;\n        boolean ccWhatsApp;\n        if ((toWhatsApp = to != null && to.toLowerCase().startsWith(WHATSAPP_PREFIX)) |\n            (ccWhatsApp = cc != null && cc.toLowerCase().startsWith(WHATSAPP_PREFIX))\n        ) {\n            Twilio.init(sid, auth);\n            String text = "*" + subject + "*" + (html ? ZHtml.toPlainText(body) : "n" + body);\n            if (toWhatsApp) {\n                Message.creator(new PhoneNumber(to), new PhoneNumber(fromNumber), text).create();\n                to = null;\n            }\n            if (ccWhatsApp) {\n                Message.creator(new PhoneNumber(cc), new PhoneNumber(fromNumber), text).create();\n                cc = null;\n            }\n        }\n        \n        \/\/ Call super for SMTP mail\n        super.send(from, to, cc, subject, body, html, highPriority);\n    }\n}<\/pre><\/div>\n\n\n\n
There are just two methods that we need to implement, or\noverride in our case. The first is configure()<\/a> (line 29). The method receives a\nparameter map that maps keys to values, which is parsed from the mail system<\/code> property of the application\u2019s configuration file<\/a>. To send a\nWhatsApp message we need three parameters:<\/p>\n\n\n\n