added /cache/stats.html for statistics / flushing

	modified:   include/cache.h
	modified:   src/cache.c
	modified:   src/server.c

include/cache.h

@@ -3,6 +3,16 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <stddef.h> // for size_t
+
+typedef struct
+{
+    size_t total_entries;  /**< Total number of cache entries. */
+    size_t exists_entries; /**< Number of cache entries where the file exists. */
+    size_t total_files;    /**< Number of files in the cache. */
+    size_t total_size;     /**< Total size of all files in the cache (in bytes). */
+    size_t memory_used;    /**< Total memory used for cache infos (in bytes). */
+} cache_stats_t;
 
 /**
  * @brief Structure representing a cache entry.
@@ -19,6 +29,26 @@ struct cache_entry_s
     const char *file_path;    /**< Path of the local cached file. */
 };
 
+/**
+ * @brief Flushes the cache by deleting local cached files and updating cache entries.
+ *
+ * This function iterates through all cache entries, deletes the associated local files if they exist,
+ * and sets the `exists` flag to `false` for each entry. It does not remove the cache entries themselves,
+ * only the cached files on disk.
+ *
+ * The function also logs the outcome of each file deletion attempt.
+ *
+ * @note This operation does not remove cache entries from memory; it only deletes the files from the file system.
+ */
+void cache_flush();
+
+/**
+ * @brief Gathers statistics about the current cache.
+ *
+ * @param stats Pointer to a structure where the statistics will be stored.
+ */
+void cache_stats(cache_stats_t *stats);
+
 /**
  * @brief Adds a new cache entry for the given URL.
  *

src/cache.c

@@ -10,6 +10,81 @@
 cache_entry_t cache_table = {.next = NULL, .hash = 0, .original_url = NULL, .cached_url = NULL, .file_path = NULL};
 uint32_t cache_entries = 0;
 
+void cache_flush()
+{
+    cache_entry_t *pos = &cache_table;
+
+    while (pos != NULL)
+    {
+        if (pos->exists)
+        {
+            // Attempt to delete the local file
+            if (pos->file_path && remove(pos->file_path) == 0)
+            {
+                TRACE_INFO("Deleted cached file: %s\n", pos->file_path);
+            }
+            else
+            {
+                TRACE_WARNING("Failed to delete cached file: %s\n", pos->file_path ? pos->file_path : "Unknown path");
+            }
+
+            // Set the exists flag to false
+            pos->exists = false;
+        }
+
+        pos = pos->next;
+    }
+}
+
+/**
+ * @brief Gathers statistics about the current cache.
+ *
+ * @param stats Pointer to a structure where the statistics will be stored.
+ */
+void cache_stats(cache_stats_t *stats)
+{
+    if (stats == NULL)
+    {
+        return;
+    }
+
+    cache_entry_t *pos = &cache_table;
+    memset(stats, 0, sizeof(cache_stats_t)); // Initialize all stats to zero
+
+    while (pos != NULL)
+    {
+        stats->total_entries++;
+        stats->memory_used += sizeof(*pos); // Add size of the cache entry structure
+
+        if (pos->original_url)
+        {
+            stats->memory_used += strlen(pos->original_url) + 1; // Add length of original_url string
+        }
+        if (pos->cached_url)
+        {
+            stats->memory_used += strlen(pos->cached_url) + 1; // Add length of cached_url string
+        }
+        if (pos->file_path)
+        {
+            stats->memory_used += strlen(pos->file_path) + 1; // Add length of file_path string
+        }
+
+        if (pos->exists)
+        {
+            stats->exists_entries++;
+
+            if (fsFileExists(pos->file_path))
+            {
+                stats->total_files++;
+                uint32_t size = 0;
+                fsGetFileSize(pos->file_path, &size);
+                stats->total_size += size;
+            }
+        }
+        pos = pos->next;
+    }
+}
+
 /**
  * @brief Caches and returns a modified base URL with trailing slashes removed.
  *

src/server.c

@@ -160,6 +160,63 @@ request_type_t request_paths[] = {
 
 error_t handleCacheDownload(HttpConnection *connection, const char_t *uri, const char_t *queryString, client_ctx_t *client_ctx)
 {
+    if (strcmp(uri, "/cache/flush") == 0)
+    {
+        cache_flush();
+
+        char *resp = "<html><body><h1>Cache Flushed</h1><p>The cache has been successfully flushed.</p><a href=\"/cache/stats.html\">Return to Cache Stats</a></body></html>";
+        httpPrepareHeader(connection, "text/html; charset=utf-8", osStrlen(resp));
+        return httpWriteResponseString(connection, resp, false);
+    }
+
+    if (strcmp(uri, "/cache/stats.html") == 0)
+    {
+        cache_stats_t stats;
+        cache_stats(&stats);
+
+        char stats_page[4096]; // Buffer for the HTML page
+        snprintf(stats_page, sizeof(stats_page),
+                 "<!DOCTYPE html>"
+                 "<html lang=\"en\">"
+                 "<head>"
+                 "<meta charset=\"UTF-8\">"
+                 "<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">"
+                 "<meta http-equiv=\"refresh\" content=\"5\">"
+                 "<title>Cache Statistics</title>"
+                 "<style>"
+                 "body { font-family: Arial, sans-serif; background-color: #f4f4f4; color: #333; }"
+                 "h1 { color: #444; text-align: center; }"
+                 ".container { max-width: 800px; margin: 50px auto; padding: 20px; background-color: #fff; box-shadow: 0 0 10px rgba(0, 0, 0, 0.1); }"
+                 "table { width: 100%%; border-collapse: collapse; margin-top: 20px; }"
+                 "th, td { padding: 12px; text-align: left; border-bottom: 1px solid #ddd; }"
+                 "th { background-color: #f2f2f2; }"
+                 ".btn { display: inline-block; padding: 10px 20px; font-size: 16px; color: #fff; background-color: #007bff; border: none; border-radius: 5px; text-decoration: none; margin-top: 20px; }"
+                 "</style>"
+                 "</head>"
+                 "<body>"
+                 "<div class=\"container\">"
+                 "<h1>Cache Statistics</h1>"
+                 "<table>"
+                 "<tr><th>Total Entries</th><td>%zu</td></tr>"
+                 "<tr><th>Entries with Existing Files</th><td>%zu</td></tr>"
+                 "<tr><th>Total Cached Files</th><td>%zu</td></tr>"
+                 "<tr><th>Total Cache Size</th><td>%zu bytes</td></tr>"
+                 "<tr><th>Memory Used</th><td>%zu bytes</td></tr>"
+                 "</table>"
+                 "<a href=\"/cache/flush\" class=\"btn\">Flush Cache</a>"
+                 "</div>"
+                 "</body>"
+                 "</html>",
+                 stats.total_entries,
+                 stats.exists_entries,
+                 stats.total_files,
+                 stats.total_size,
+                 stats.memory_used);
+
+        httpPrepareHeader(connection, "text/html; charset=utf-8", osStrlen(stats_page));
+        return httpWriteResponseString(connection, stats_page, false);
+    }
+
     cache_entry_t *entry = cache_fetch_by_path(uri);
     if (!entry)
     {