-move templating library into exchange.git

1 files changed, 449 insertions, 0 deletions

diff --git a/src/templating/templating_api.c b/src/templating/templating_api.c
new file mode 100644
index 000000000..6d5c7c791
--- /dev/null
+++ b/src/templating/templating_api.c
@@ -0,0 +1,449 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2020, 2022 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file templating_api.c
+ * @brief logic to load and complete HTML templates
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_util.h"
+#include "taler_mhd_lib.h"
+#include "taler_templating_lib.h"
+#include "mustach.h"
+#include "mustach-jansson.h"
+#include <gnunet/gnunet_mhd_compat.h>
+
+
+/**
+ * Entry in a key-value array we use to cache templates.
+ */
+struct TVE
+{
+  /**
+   * A name, used as the key. NULL for the last entry.
+   */
+  char *name;
+
+  /**
+   * Language the template is in.
+   */
+  char *lang;
+
+  /**
+   * 0-terminated (!) file data to return for @e name and @e lang.
+   */
+  char *value;
+
+};
+
+
+/**
+ * Array of templates loaded into RAM.
+ */
+static struct TVE *loaded;
+
+/**
+ * Length of the #loaded array.
+ */
+static unsigned int loaded_length;
+
+
+/**
+ * Load Mustach template into memory.  Note that we intentionally cache
+ * failures, that is if we ever failed to load a template, we will never try
+ * again.
+ *
+ * @param connection the connection we act upon
+ * @param name name of the template file to load
+ *        (MUST be a 'static' string in memory!)
+ * @return NULL on error, otherwise the template
+ */
+static const char *
+lookup_template (struct MHD_Connection *connection,
+                 const char *name)
+{
+  struct TVE *best = NULL;
+  const char *lang;
+
+  lang = MHD_lookup_connection_value (connection,
+                                      MHD_HEADER_KIND,
+                                      MHD_HTTP_HEADER_ACCEPT_LANGUAGE);
+  if (NULL == lang)
+    lang = "en";
+  /* find best match by language */
+  for (unsigned int i = 0; i<loaded_length; i++)
+  {
+    if (0 != strcmp (loaded[i].name,
+                     name))
+      continue; /* does not match by name */
+    if ( (NULL == best) ||
+         (TALER_language_matches (lang,
+                                  loaded[i].lang) >
+          TALER_language_matches (lang,
+                                  best->lang) ) )
+      best = &loaded[i];
+  }
+  if (NULL == best)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "No templates found in `%s'\n",
+                name);
+    return NULL;
+  }
+  return best->value;
+}
+
+
+/**
+ * Get the base URL for static resources.
+ *
+ * @param con the MHD connection
+ * @param instance_id the instance ID
+ * @returns the static files base URL, guaranteed
+ *          to have a trailing slash.
+ */
+static char *
+make_static_url (struct MHD_Connection *con,
+                 const char *instance_id)
+{
+  const char *host;
+  const char *forwarded_host;
+  const char *uri_path;
+  struct GNUNET_Buffer buf = { 0 };
+
+  host = MHD_lookup_connection_value (con,
+                                      MHD_HEADER_KIND,
+                                      "Host");
+  forwarded_host = MHD_lookup_connection_value (con,
+                                                MHD_HEADER_KIND,
+                                                "X-Forwarded-Host");
+
+  uri_path = MHD_lookup_connection_value (con,
+                                          MHD_HEADER_KIND,
+                                          "X-Forwarded-Prefix");
+  if (NULL != forwarded_host)
+    host = forwarded_host;
+
+  if (NULL == host)
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  GNUNET_assert (NULL != instance_id);
+
+  if (GNUNET_NO == TALER_mhd_is_https (con))
+    GNUNET_buffer_write_str (&buf,
+                             "http://");
+  else
+    GNUNET_buffer_write_str (&buf,
+                             "https://");
+  GNUNET_buffer_write_str (&buf,
+                           host);
+  if (NULL != uri_path)
+    GNUNET_buffer_write_path (&buf,
+                              uri_path);
+  if (0 != strcmp ("default",
+                   instance_id))
+  {
+    GNUNET_buffer_write_path (&buf,
+                              "instances");
+    GNUNET_buffer_write_path (&buf,
+                              instance_id);
+  }
+  GNUNET_buffer_write_path (&buf,
+                            "static/");
+  return GNUNET_buffer_reap_str (&buf);
+}
+
+
+/**
+ * Load a @a template and substitute using @a root, returning
+ * the result to the @a connection with the given
+ * @a http_status code.
+ *
+ * @param connection the connection we act upon
+ * @param http_status code to use on success
+ * @param template basename of the template to load
+ * @param instance_id instance ID, used to compute static files URL
+ * @param taler_uri value for "Taler:" header to set, or NULL
+ * @param root JSON object to pass as the root context
+ * @return #GNUNET_OK on success (reply queued), #GNUNET_NO if an error was queued,
+ *         #GNUNET_SYSERR on failure (to queue an error)
+ */
+enum GNUNET_GenericReturnValue
+TALER_TEMPLATING_reply (struct MHD_Connection *connection,
+                        unsigned int http_status,
+                        const char *template,
+                        const char *instance_id,
+                        const char *taler_uri,
+                        json_t *root)
+{
+  struct MHD_Response *reply;
+  char *body;
+  size_t body_size;
+
+  {
+    const char *tmpl;
+    int eno;
+
+    tmpl = lookup_template (connection,
+                            template);
+    if (NULL == tmpl)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Failed to load template `%s'\n",
+                  template);
+      if (MHD_YES !=
+          TALER_MHD_reply_with_error (connection,
+                                      MHD_HTTP_NOT_ACCEPTABLE,
+                                      TALER_EC_GENERIC_FAILED_TO_LOAD_TEMPLATE,
+                                      template))
+        return GNUNET_SYSERR;
+      return GNUNET_NO;
+    }
+    /* Add default values to the context */
+    {
+      char *static_url = make_static_url (connection,
+                                          instance_id);
+      json_object_set (root,
+                       "static_url",
+                       json_string (static_url));
+      GNUNET_free (static_url);
+    }
+    if (0 !=
+        (eno = mustach_jansson (tmpl,
+                                root,
+                                &body,
+                                &body_size)))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "mustach failed on template `%s' with error %d\n",
+                  template,
+                  eno);
+      if (MHD_YES !=
+          TALER_MHD_reply_with_error (connection,
+                                      MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                      TALER_EC_GENERIC_FAILED_TO_EXPAND_TEMPLATE,
+                                      template))
+        return GNUNET_SYSERR;
+      return GNUNET_NO;
+    }
+  }
+
+  /* try to compress reply if client allows it */
+  {
+    bool compressed = false;
+
+    if (MHD_YES ==
+        TALER_MHD_can_compress (connection))
+    {
+      compressed = TALER_MHD_body_compress ((void **) &body,
+                                            &body_size);
+    }
+    reply = MHD_create_response_from_buffer (body_size,
+                                             body,
+                                             MHD_RESPMEM_MUST_FREE);
+    if (NULL == reply)
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+    if (compressed)
+    {
+      if (MHD_NO ==
+          MHD_add_response_header (reply,
+                                   MHD_HTTP_HEADER_CONTENT_ENCODING,
+                                   "deflate"))
+      {
+        GNUNET_break (0);
+        MHD_destroy_response (reply);
+        return GNUNET_SYSERR;
+      }
+    }
+  }
+
+  /* Add standard headers */
+  if (NULL != taler_uri)
+    GNUNET_break (MHD_NO !=
+                  MHD_add_response_header (reply,
+                                           "Taler",
+                                           taler_uri));
+  GNUNET_break (MHD_NO !=
+                MHD_add_response_header (reply,
+                                         MHD_HTTP_HEADER_CONTENT_TYPE,
+                                         "text/html"));
+
+  /* Actually return reply */
+  {
+    MHD_RESULT ret;
+
+    ret = MHD_queue_response (connection,
+                              http_status,
+                              reply);
+    MHD_destroy_response (reply);
+    if (MHD_NO == ret)
+      return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function called with a template's filename.
+ *
+ * @param cls closure
+ * @param filename complete filename (absolute path)
+ * @return #GNUNET_OK to continue to iterate,
+ *  #GNUNET_NO to stop iteration with no error,
+ *  #GNUNET_SYSERR to abort iteration with error!
+ */
+static enum GNUNET_GenericReturnValue
+load_template (void *cls,
+               const char *filename)
+{
+  char *lang;
+  char *end;
+  int fd;
+  struct stat sb;
+  char *map;
+  const char *name;
+
+  if ('.' == filename[0])
+    return GNUNET_OK;
+
+  name = strrchr (filename,
+                  '/');
+  if (NULL == name)
+    name = filename;
+  else
+    name++;
+  lang = strchr (name,
+                 '.');
+  if (NULL == lang)
+    return GNUNET_OK; /* name must include .$LANG */
+  lang++;
+  end = strchr (lang,
+                '.');
+  if ( (NULL == end) ||
+       (0 != strcmp (end,
+                     ".must")) )
+    return GNUNET_OK; /* name must end with '.must' */
+
+  /* finally open template */
+  fd = open (filename,
+             O_RDONLY);
+  if (-1 == fd)
+  {
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
+                              "open",
+                              filename);
+
+    return GNUNET_SYSERR;
+  }
+  if (0 !=
+      fstat (fd,
+             &sb))
+  {
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
+                              "open",
+                              filename);
+    GNUNET_break (0 == close (fd));
+    return GNUNET_OK;
+  }
+  map = GNUNET_malloc_large (sb.st_size + 1);
+  if (NULL == map)
+  {
+    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
+                         "malloc");
+    GNUNET_break (0 == close (fd));
+    return GNUNET_SYSERR;
+  }
+  if (sb.st_size !=
+      read (fd,
+            map,
+            sb.st_size))
+  {
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
+                              "read",
+                              filename);
+    GNUNET_break (0 == close (fd));
+    return GNUNET_OK;
+  }
+  GNUNET_break (0 == close (fd));
+  GNUNET_array_grow (loaded,
+                     loaded_length,
+                     loaded_length + 1);
+  loaded[loaded_length - 1].name = GNUNET_strndup (name,
+                                                   (lang - 1) - name);
+  loaded[loaded_length - 1].lang = GNUNET_strndup (lang,
+                                                   end - lang);
+  loaded[loaded_length - 1].value = map;
+  return GNUNET_OK;
+}
+
+
+enum GNUNET_GenericReturnValue
+TALER_TEMPLATING_init (const char *subsystem)
+{
+  char *dn;
+  int ret;
+
+  {
+    char *path;
+
+    path = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_DATADIR);
+    if (NULL == path)
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
+    GNUNET_asprintf (&dn,
+                     "%s/%s/templates/",
+                     subsystem,
+                     path);
+    GNUNET_free (path);
+  }
+  ret = GNUNET_DISK_directory_scan (dn,
+                                    &load_template,
+                                    NULL);
+  GNUNET_free (dn);
+  if (-1 == ret)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+void
+TALER_TEMPLATING_done (void)
+{
+  for (unsigned int i = 0; i<loaded_length; i++)
+  {
+    GNUNET_free (loaded[i].name);
+    GNUNET_free (loaded[i].lang);
+    GNUNET_free (loaded[i].value);
+  }
+  GNUNET_array_grow (loaded,
+                     loaded_length,
+                     0);
+}
+
+
+/* end of templating_api.c */