From d87d5a6c242a6ab98c01b32c75dafe1d62e9d7b9 Mon Sep 17 00:00:00 2001
From: "B. Endres" <endres@systopia.de>
Date: Fri, 4 Jan 2019 16:22:43 +0100
Subject: [PATCH] [#32] implementing webhook2api

---
 proxy/webhook2api.php | 247 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 247 insertions(+)
 create mode 100644 proxy/webhook2api.php

diff --git a/proxy/webhook2api.php b/proxy/webhook2api.php
new file mode 100644
index 0000000..7579223
--- /dev/null
+++ b/proxy/webhook2api.php
@@ -0,0 +1,247 @@
+<?php
+/*--------------------------------------------------------+
+| SYSTOPIA CiviProxy                                      |
+|  a simple proxy solution for external access to CiviCRM |
+| Copyright (C) 2019 SYSTOPIA                             |
+| Author: B. Endres (endres -at- systopia.de)             |
+| http://www.systopia.de/                                 |
++---------------------------------------------------------*/
+
+require_once "config.php";
+require_once "proxy.php";
+
+// first check if webhooks are enabled
+if (empty($webhook2api)) civiproxy_http_error("Feature disabled", 405);
+
+// basic check
+if (!civiproxy_security_check('webhook2api')) {
+  civiproxy_http_error("Access denied", 403);
+}
+
+// find the right configuration
+if (!empty($_REQUEST['id']) && isset($webhook2api['configurations'][$_REQUEST['id']])) {
+  // we found the if in the configurations
+  $configurations = [$webhook2api['configurations'][$_REQUEST['id']]];
+} elseif (empty($_REQUEST['id']) && isset($webhook2api['configurations']['default'])) {
+  // this is teh default configuration
+  $configurations = [$webhook2api['configurations']['default']];
+} else {
+  // use all of them (first one matching is executed)
+  $configurations = $webhook2api['configurations'];
+}
+
+// read some input
+$post_input = @file_get_contents('php://input');
+
+// MAIN: iterate through all (eligible) configurations
+$last_error = ["No handler found", 501];
+foreach ($configurations as $configuration) {
+  $last_error = webhook2api_processConfiguration($configuration, $post_input);
+  if ($last_error == NULL) {
+    // success!
+    break;
+  }
+}
+
+// finally - if there was only errors, return the last one
+if ($last_error) {
+  civiproxy_http_error($last_error[0], $last_error[1]);
+}
+
+
+
+
+/**
+ * Apply the given configuration. If it matches and executes,
+ *  it returns NULL, otherwise
+ *
+ * @param $configuration array configuration/specification
+ * @return null|array [status_code, error message]
+ */
+function webhook2api_processConfiguration($configuration, $post_input) {
+  // check the IP/range restrictions
+  if (!empty($configuration['ip_sources']) && is_array($configuration['ip_sources'])) {
+    $ip = $_SERVER['REMOTE_ADDR'];
+    $access_granted = FALSE;
+    foreach ($configuration['ip_sources'] as $netmask) {
+      // copied from https://secure.php.net/manual/de/ref.network.php
+      list ($net, $mask) = explode("/", $netmask);
+      $ip_net = ip2long ($net);
+      $ip_mask = ~((1 << (32 - $mask)) - 1);
+      $ip_ip = ip2long ($ip);
+      $ip_ip_net = $ip_ip & $ip_mask;
+      if ($ip_ip_net == $ip_net) {
+        $access_granted = TRUE;
+        break;
+      }
+    }
+    if (!$access_granted) {
+      // this configuration is not eligible
+      return ["Access denied", 403];
+    }
+  }
+
+  // gather source data
+  $data = [];
+  if (!empty($configuration['data_sources']) && is_array($configuration['data_sources'])) {
+    foreach ($configuration['data_sources'] as $data_source) {
+      switch ($data_source) {
+        case 'POST/json': # JSON data in POST field
+          $more_data = json_decode($post_input, TRUE);
+          $data = array_merge_recursive($data, $more_data);
+          break;
+        case 'REQUEST': # simple request parameters
+          $data = array_merge_recursive($data, $_REQUEST);
+          break;
+        default:
+          civiproxy_log("Webhook2API[{$configuration['name']}]: unknown source '{$data_source}' in configuration. Ignored.");
+      }
+    }
+  }
+
+  // evaluate sentinels
+  if (!empty($configuration['sentinel']) && is_array($configuration['sentinel'])) {
+    foreach ($configuration['sentinel'] as $sentinel) {
+      list($value_source, $check) = $sentinel;
+      $value = webhook2api_getValue($data, $value_source);
+      if (substr($check, 0, 6) == "equal:") {
+        // check if terms a equal
+        if (substr($check, 6) != $value) {
+          return ["Access denied", 403];
+        }
+      } else {
+        // unknown instruction
+        civiproxy_log("Webhook2API[{$configuration['name']}]: don't understad sentinel '{$check}'. Ignored.");
+      }
+    }
+  }
+
+  // compile API query
+  $params = [];
+  if (!empty($configuration['parameter_mapping']) && is_array($configuration['parameter_mapping'])) {
+    foreach ($configuration['parameter_mapping'] as $mapping) {
+      $source_path = $mapping[0];
+      $target_path = $mapping[1];
+      $modifiers   = isset($mapping[2]) ? $mapping[2] : [];
+
+      // get value
+      $value = webhook2api_getValue($data, $source_path);
+
+      // run modifiers
+      foreach ($modifiers as $modifier) {
+        // TODO:
+      }
+
+      // set to target
+      webhook2api_setValue($params, $target_path, $value);
+    }
+  } else {
+    $params = $data;
+  }
+
+  // sanitise data
+  if (!empty($configuration['parameter_sanitation']) && is_array($configuration['parameter_sanitation'])) {
+    // TODO: implement
+  }
+
+  // send to target REST API
+  if (empty($configuration['entity']) || empty($configuration['action'])) {
+    civiproxy_log("Webhook2API[{$configuration['name']}]: Missing entity/action.");
+    return ["Configuration error", 403];
+  }
+  if (empty($configuration['api_key'])) {
+    civiproxy_log("Webhook2API[{$configuration['name']}]: Missing api_key.");
+    return ["Configuration error", 403];
+  }
+  $result = civicrm_api3($configuration['entity'], $configuration['action'], $params);
+
+  // process result
+  if (!empty($configuration['response_mapping']) && is_array($configuration['response_mapping'])) {
+    // TODO: implement
+
+  } else {
+    // default behaviour:
+    if (empty($result['is_error'])) {
+      http_response_code(200);
+    } else {
+      if (!empty($result['http_code'])) {
+        http_response_code($result['http_code']);
+      } else {
+        http_response_code(403);
+      }
+    }
+  }
+
+  // all done
+  exit();
+}
+
+/**
+ * Get the value from a multidimensional array,
+ *  specified by the path
+ *
+ * @param $data array         multidimensional data array
+ * @param $path array|string  path description
+ * @return mixed value
+ */
+function webhook2api_getValue($data, $path) {
+  if (is_string($path)) {
+    if (isset($data[$path])) {
+      return $data[$path];
+    } else {
+      return NULL;
+    }
+  } elseif (is_array($path)) {
+    if (count($path) == 0) {
+      return NULL;
+    } elseif (count($path) == 1) {
+      return webhook2api_getValue($data, $path[0]);
+    } else {
+      $path_element = array_shift($path);
+      $sub_data = webhook2api_getValue($data, $path_element);
+      if (is_array($sub_data)) {
+        return webhook2api_getValue($sub_data, $path);
+      } else {
+        return NULL;
+      }
+    }
+  }
+}
+
+/**
+ * Set the value from a multidimensional array as specified by the path
+ *
+ * @param $data        array the data
+ * @param $target_path array destination
+ * @param $value       mixed value
+ */
+function webhook2api_setValue(&$data, $target_path, $value) {
+  if (is_array($target_path)) {
+    if (count($target_path) == 0) {
+      // error - bad spec
+      return;
+
+    } elseif (count($target_path) == 1) {
+      // last element -> set value
+      $data[$target_path[0]] = $value;
+
+    } else {
+      // not last element
+      $element = array_shift($target_path);
+      if (!isset($data[$element])) {
+        $data[$element] = [];
+      }
+      if (is_array($data[$element])) {
+        webhook2api_setValue($data[$element], $target_path, $value);
+      } else {
+        // error - bad spec (path element is not array)
+      }
+    }
+
+  } elseif (is_string($target_path)) {
+    webhook2api_setValue($data, [$target_path], $value);
+
+  } else {
+    // error - bad spec
+  }
+}
\ No newline at end of file