WIP:base implementation of replacement mail manager based on libcurl

src/smtpManager.cpp

@@ -0,0 +1,157 @@
+#ifndef SMTP_MANAGER_CPP
+#define SMTP_MANAGER_CPP
+
+#include <iostream>
+#include <vector>
+#include <iomanip>
+#include <ctime>
+#include <curl/curl.h>
+
+#include "utilities.cpp"
+
+
+
+namespace SMTPManager {
+    static const std::string END_OF_LINE = "\r\n";
+    static const std::string END_OF_MAIL = "\0";
+
+    struct payload {
+        int lines_read = 0;
+        std::vector<std::string> payload_data;
+    };
+
+    /*
+     * Generates the Date Time Header Segment
+     * Date: {day}/{month}/{year} {hour}:{minute}:{second} {delta to UTC} \r\n
+     */
+    std::string generateEmailSegmentDateTime() {
+        std::time_t time = std::time(nullptr);
+        std::tm localTime = *std::localtime(&time);
+        std::ostringstream oss;
+        oss << "Date: " << std::put_time(&localTime, "%d/%m/%Y %H:%M:%S %z") << END_OF_LINE;
+        return oss.str();
+    }
+
+    /*
+     * Generates the Recipient Header Segment
+     * To: {Recipient Name} <{email address}>\r\n
+     */
+    std::string generateEmailSegmentRecipient(const std::string &recipientName, const std::string &recipientEmail) {
+        return "To: " + recipientName + " <" + recipientEmail + ">" + END_OF_LINE;
+    }
+
+    /*
+     * Generates the Sender Header Segment
+     * From: {Sender Name} <{email address}>\r\n
+     */
+    std::string generateEmailSegmentSender(const Utilities::config &configuration) {
+        return "From: " + configuration.emailAddressDisplay + " <" + configuration.emailAddress + ">" + END_OF_LINE;
+    }
+
+    /*
+     * Generates the Subject Header Segment
+     * Subject: {subject}\r\n
+     */
+    std::string generateEmailSegmentSubject(const std::string &emailSubject) {
+        return "Subject: " + emailSubject + END_OF_LINE;
+    }
+
+    /*
+     * Generates the Content-Type Header Segment
+     */
+    std::string generateEmailSegmentContentType() {
+        return "Content-Type: text/html; charset=UTF-8" + END_OF_LINE;
+    }
+
+
+    /*
+     * Generates a line for the body
+     * {bodyLine}\r\n
+     */
+    std::string generateEmailSegmentBody(const std::string &body) {
+        return body + END_OF_LINE;
+    }
+
+    void fillEmailPayloadData(struct payload &payload, const Utilities::config &configuration, const std::string &recipientEmail, const std::string &recipientName, const std::string &emailSubject, const std::string &body) {
+        payload.payload_data.emplace_back(generateEmailSegmentDateTime());
+        payload.payload_data.emplace_back(generateEmailSegmentRecipient(recipientName, recipientEmail));
+        payload.payload_data.emplace_back(generateEmailSegmentSender(configuration));
+        payload.payload_data.emplace_back(generateEmailSegmentSubject(emailSubject));
+        payload.payload_data.emplace_back(generateEmailSegmentContentType());
+        payload.payload_data.emplace_back(END_OF_LINE);
+        payload.payload_data.emplace_back(generateEmailSegmentBody(body));
+        payload.payload_data.emplace_back(END_OF_MAIL);
+    }
+
+    /*
+     * curl read callback function
+     */
+    size_t payload_source(void *ptr, size_t size, size_t nmemb, void *userp)
+    {
+        auto* payload_context = (struct payload*)userp;
+        const char *data;
+
+        if((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) {
+            return 0;
+        }
+
+        data = payload_context->payload_data[payload_context->lines_read].c_str();
+
+        if(data) {
+            size_t len = strlen(data);
+            memcpy(ptr, data, len);
+            payload_context->lines_read++;
+            return len;
+        }
+        return 0;
+    }
+
+    /*
+     * Generates the SMTP URL
+     * "smtp://{address}:{port}"
+     */
+    std::string generateMailServerURL(const Utilities::config &configuration) {
+        return "smtp://" + configuration.emailServerAddress + ":" + std::to_string(configuration.emailServerPort);
+    }
+
+    /*
+     * todo:for some inexplicable reason the sent email contains an empty CC: field which needs some examination
+     * todo:validate header https://mailheader.org/show.cgi
+     * Sends an HTML Email using curl
+     * returns CURL Error Codes https://curl.se/libcurl/c/libcurl-errors.html
+     * 1 = OK
+     */
+    int sendEmailNew(const Utilities::config &configuration, const std::string &recipientEmail, const std::string &emailSubject, const std::string &htmlBody) {
+        struct payload payload;
+        fillEmailPayloadData(payload, configuration, recipientEmail, "tmpString", emailSubject, htmlBody);//todo:change
+        CURL* curl;
+        CURLcode res = CURLE_OK;
+        struct curl_slist* recipients;
+        recipients = curl_slist_append(nullptr, "root@localhost");
+        curl = curl_easy_init();
+        if (curl) {
+            curl_easy_setopt(curl, CURLOPT_USERNAME, configuration.emailAddress.c_str());
+            curl_easy_setopt(curl, CURLOPT_PASSWORD, configuration.emailPassword.c_str());
+            curl_easy_setopt(curl, CURLOPT_URL, generateMailServerURL(configuration).c_str());
+            curl_easy_setopt(curl, CURLOPT_USE_SSL, (long)CURLUSESSL_ALL);
+            curl_easy_setopt(curl, CURLOPT_MAIL_FROM, configuration.emailAddress.c_str());
+            recipients = curl_slist_append(recipients, recipientEmail.c_str());
+            curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
+            curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
+            curl_easy_setopt(curl, CURLOPT_READDATA, &payload);
+            curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
+            curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
+            res = curl_easy_perform(curl);
+
+            if (res != CURLE_OK)
+                fprintf(stderr, "curl_easy_perform() failed: %s\n",
+                        curl_easy_strerror(res));
+
+            curl_slist_free_all(recipients);
+
+            curl_easy_cleanup(curl);
+        }
+        return (int)res;
+    }
+}
+#endif