Added main files.

Author: judgej

Diff for: .htaccess

@@ -0,0 +1,4 @@
+Order Deny,Allow
+Allow from all
+# ALLOW-LIST-START
+# ALLOW-LIST-END

Diff for: allowme_config.php

@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * TODO: use a more flexible config file package.
+ */
+
+return array(
+    // Start and end markers.
+    // Only "allow from" statements will appear between these markers.
+    // The markers must be present once only, and in the correct order.
+
+    'marker_start' => '# ALLOW-LIST-START',
+    'marker_end' => '# ALLOW-LIST-END',
+
+    // Password to get yourself added to the list.
+    'password' => 'whatever',
+
+    // Location of the htaccess file to update.
+    'htaccess' => __DIR__ . '/../.htaccess',
+
+    // Newlines to use when generating the file.
+    'newline' => "\n",
+
+    // Header code, if placing markers for the first time.
+    'header' => array(
+        '# Section added by allowme script ' . date('Y-m-d'),
+        'Order Deny,Allow',
+        'Deny from all'
+    ),
+
+);

Diff for: index.php

@@ -0,0 +1,110 @@
+<?php
+
+/**
+ * Maintain dynamic allow list in .htaccess
+ *
+ * By visiting this script with the correct password, your
+ * IP address will be added to the allow list in the
+ * .htaccess file.
+ *
+ * TODO: ability to lock the file, so two processes do not write to
+ * it at the same time.
+ * There is an assumption that the htaccess file will not be too long,
+ * and so can be easily processes in memory.
+ * TODO: Take a backup of the file before writing.
+ * TODO: if htaccess does not contain any markers, then place a pair
+ * right at the start, with appropriate deny statements. [DONE]
+ * FIXME: a blank line is being added to the end of the file, each time an
+ * IP address is added. [HACK: remove *any* blank lines from the end]
+ */
+
+// TODO: use a package to get the config data, which can include defaults
+// and overrides, and perhaps a config directory.
+$config = include('allowme_config.php');
+
+$nl = $config['newline'];
+
+// Read teh current htaccess file into three variables: before, within, 
+// and after the section to update.
+
+// So we can detect various line endings when reading the htaccess file.
+ini_set('auto_detect_line_endings',true);
+
+$content = array(
+    'before' => '',
+    'marker_start' => $config['marker_start'] . $nl,
+    'within' => '',
+    'marker_end' => $config['marker_end'] . $nl,
+    'after' => ''
+);
+
+$state = 'before';
+
+if (!file_exists($config['htaccess'])) die('htaccess file not found');
+if (!is_writable($config['htaccess'])) die('htaccess file not writable');
+
+$fd = fopen($config['htaccess'], 'r');
+while(!feof($fd)) {
+    // Get the line, removing any end-of-line characters it may have.
+    // Use a regex to support multiple line-end characters in any order.
+    $line = preg_replace('/[\r\n]*$/', '', fgets($fd));
+
+    if (trim($line) == $config['marker_start']) {
+        if ($state != 'before') die('Out of order markers');
+        $state = 'within';
+        continue;
+    }
+
+    if (trim($line) == $config['marker_end']) {
+        if ($state != 'within') die('Out of order markers');
+        $state = 'after';
+        continue;
+    }
+
+    $content[$state] .= $line . $nl;
+    //echo "line=$line; ";
+}
+fclose($fd);
+
+// Now we should have the file in three sections.
+// If we do not, then the markers were missing.
+
+if ($state == 'within') die('Missing or invalid markers');
+
+if ($state == 'before') {
+    // We never found the markers, so add them now, right at the
+    // start of the file.
+
+    // Move the before section to the end, with a blank line before it.
+    $content['after'] = $nl . $content['before'];
+    $content['before'] = implode($nl, $config['header']) . $nl;
+}
+
+// Get the user's IP.
+$ip = $_SERVER['REMOTE_ADDR'];
+
+if (empty($ip) || !preg_match('/^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$/', $ip)) die('IP address not known');
+
+// Look to see if the IP address is already there.
+if (preg_match('/ '.$ip.'[^0-9]/', $content['within'])) die('IP already listed');
+
+// Still here? Add this IP.
+
+$content['within'] = 'Allow from ' . $ip . $nl . $content['within'];
+
+// Flatten the new file content.
+$flattened = array_reduce(
+    $content, 
+    function(&$result, $item) {return $result . $item;},
+    ''
+);
+
+// Remove blank lines from the end. This is a sort of hack.
+$flattened = preg_replace('/['.$nl.']+$/', $nl, $flattened);
+
+// Now write the whole file.
+file_put_contents($config['htaccess'], $flattened, LOCK_EX);
+
+echo "IP added";
+
+//echo "<pre>"; var_dump($flattened); echo "</pre>";