implement i18n lookup logic for #6458

src/include/taler_json_lib.h

@@ -293,6 +293,37 @@ TALER_JSON_exchange_wire_signature_make (
   const struct TALER_MasterPrivateKeyP *master_priv);
 
 
+/**
+ * Extract a string from @a object under the field @a field, but respecting
+ * the Taler i18n rules and the language preferences expressed in @a
+ * language_pattern.
+ *
+ * Basically, the @a object may optionally contain a sub-object
+ * "${field}_i18n" with a map from IETF BCP 47 language tags to a localized
+ * version of the string. If this map exists and contains an entry that
+ * matches the @a language pattern, that object (usually a string) is
+ * returned. If the @a language_pattern does not match any entry, or if the
+ * i18n sub-object does not exist, we simply return @a field of @a object
+ * (also usually a string).
+ *
+ * If @a object does not have a member @a field we return NULL (error).
+ *
+ * @param object the object to extract internationalized
+ *        content from
+ * @param language_pattern a language preferences string
+ *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1", following
+ *        https://tools.ietf.org/html/rfc7231#section-5.3.1
+ * @param field name of the field to extract
+ * @return NULL on error, otherwise the member from
+ *        @a object. Note that the reference counter is
+ *        NOT incremented.
+ */
+const json_t *
+TALER_JSON_extract_i18n (const json_t *object,
+                         const char *language_pattern,
+                         const char *field);
+
+
 /**
  * Obtain the wire method associated with the given
  * wire account details.  @a wire_s must contain a payto://-URL

src/include/taler_mhd_lib.h

@@ -96,22 +96,6 @@ MHD_RESULT
 TALER_MHD_can_compress (struct MHD_Connection *connection);
 
 
-/**
- * Check if @a lang matches the @a language_pattern, and if so with
- * which preference.
- * See also: https://tools.ietf.org/html/rfc7231#section-5.3.1
- *
- * @param language_pattern a language preferences string
- *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1"
- * @param lang the 2-digit language to match
- * @return q-weight given for @a lang in @a language_pattern, 1.0 if no weights are given;
- *         0 if @a lang is not in @a language_pattern
- */
-double
-TALER_MHD_language_matches (const char *language_pattern,
-                            const char *lang);
-
-
 /**
  * Send JSON object as response.
  *

src/include/taler_util.h

@@ -184,6 +184,22 @@ char *
 TALER_urlencode (const char *s);
 
 
+/**
+ * Check if @a lang matches the @a language_pattern, and if so with
+ * which preference.
+ * See also: https://tools.ietf.org/html/rfc7231#section-5.3.1
+ *
+ * @param language_pattern a language preferences string
+ *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1"
+ * @param lang the 2-digit language to match
+ * @return q-weight given for @a lang in @a language_pattern, 1.0 if no weights are given;
+ *         0 if @a lang is not in @a language_pattern
+ */
+double
+TALER_language_matches (const char *language_pattern,
+                        const char *lang);
+
+
 /**
  * Find out if an MHD connection is using HTTPS (either
  * directly or via proxy).

src/json/Makefile.am

@@ -10,6 +10,7 @@ lib_LTLIBRARIES = \
   libtalerjson.la
 
 libtalerjson_la_SOURCES = \
+  i18n.c \
   json.c \
   json_helper.c \
   json_wire.c

src/json/i18n.c

@@ -0,0 +1,95 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2020 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 json/i18n.c
+ * @brief helper functions for i18n in JSON processing
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_util.h"
+#include "taler_json_lib.h"
+
+
+/**
+ * Extract a string from @a object under the field @a field, but respecting
+ * the Taler i18n rules and the language preferences expressed in @a
+ * language_pattern.
+ *
+ * Basically, the @a object may optionally contain a sub-object
+ * "${field}_i18n" with a map from IETF BCP 47 language tags to a localized
+ * version of the string. If this map exists and contains an entry that
+ * matches the @a language pattern, that object (usually a string) is
+ * returned. If the @a language_pattern does not match any entry, or if the
+ * i18n sub-object does not exist, we simply return @a field of @a object
+ * (also usually a string).
+ *
+ * If @a object does not have a member @a field we return NULL (error).
+ *
+ * @param object the object to extract internationalized
+ *        content from
+ * @param language_pattern a language preferences string
+ *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1", following
+ *        https://tools.ietf.org/html/rfc7231#section-5.3.1
+ * @param field name of the field to extract
+ * @return NULL on error, otherwise the member from
+ *        @a object. Note that the reference counter is
+ *        NOT incremented.
+ */
+const json_t *
+TALER_JSON_extract_i18n (const json_t *object,
+                         const char *language_pattern,
+                         const char *field)
+{
+  const json_t *ret;
+  json_t *i18n;
+  double quality = -1;
+
+  ret = json_object_get (object,
+                         field);
+  if (NULL == ret)
+    return NULL; /* field MUST exist in object */
+  {
+    char *name;
+
+    GNUNET_asprintf (&name,
+                     "%s_i18n",
+                     field);
+    i18n = json_object_get (object,
+                            name);
+    GNUNET_free (name);
+  }
+  if (NULL == i18n)
+    return ret;
+  {
+    const char *key;
+    json_t *value;
+
+    json_object_foreach (i18n, key, value) {
+      double q = TALER_language_matches (language_pattern,
+                                         key);
+      if (q > quality)
+      {
+        quality = q;
+        ret = value;
+      }
+    }
+  }
+  return ret;
+}
+
+
+/* end of i18n.c */

src/mhd/mhd_legal.c

@@ -154,52 +154,6 @@ xmime_matches (const char *accept_pattern,
 }
 
 
-/**
- * Check if @a lang matches the @a language_pattern, and if so with
- * which preference.
- * See also: https://tools.ietf.org/html/rfc7231#section-5.3.1
- *
- * @param language_pattern a language preferences string
- *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1"
- * @param lang the 2-digit language to match
- * @return q-weight given for @a lang in @a language_pattern, 1.0 if no weights are given;
- *         0 if @a lang is not in @a language_pattern
- */
-double
-TALER_MHD_language_matches (const char *language_pattern,
-                            const char *lang)
-{
-  char *p = GNUNET_strdup (language_pattern);
-  char *sptr;
-  double r = 0.0;
-
-  for (char *tok = strtok_r (p, ",", &sptr);
-       NULL != tok;
-       tok = strtok_r (NULL, ",", &sptr))
-  {
-    char *sptr2;
-    char *lp = strtok_r (tok, ";", &sptr2);
-    char *qp = strtok_r (NULL, ";", &sptr2);
-    double q = 1.0;
-
-    while (isspace ((int) *lp))
-      lp++;
-    if (NULL != qp)
-      while (isspace ((int) *qp))
-        qp++;
-    GNUNET_break_op ( (NULL == qp) ||
-                      (1 == sscanf (qp,
-                                    "q=%lf",
-                                    &q)) );
-    if (0 == strcasecmp (lang,
-                         lp))
-      r = GNUNET_MAX (r, q);
-  }
-  GNUNET_free (p);
-  return r;
-}
-
-
 /**
  * Generate a response with a legal document in the format and language of the
  * user's choosing.
@@ -271,10 +225,10 @@ TALER_MHD_reply_legal (struct MHD_Connection *conn,
         if ( (NULL == t) ||
              (! xmime_matches (mime,
                                t->mime_type)) ||
-             (TALER_MHD_language_matches (lang,
-                                          p->language) >
-              TALER_MHD_language_matches (lang,
-                                          t->language) ) )
+             (TALER_language_matches (lang,
+                                      p->language) >
+              TALER_language_matches (lang,
+                                      t->language) ) )
           t = p;
       }
     }

src/util/Makefile.am

@@ -38,6 +38,7 @@ libtalerutil_la_SOURCES = \
   crypto.c \
   crypto_wire.c \
   getopt.c \
+  lang.c \
   mhd.c \
   payto.c \
   taler_error_codes.c \

src/util/lang.c

@@ -0,0 +1,71 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2020 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 lang.c
+ * @brief Utility functions for parsing and matching RFC 7231 language strings.
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "taler_util.h"
+
+
+/**
+ * Check if @a lang matches the @a language_pattern, and if so with
+ * which preference.
+ * See also: https://tools.ietf.org/html/rfc7231#section-5.3.1
+ *
+ * @param language_pattern a language preferences string
+ *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1"
+ * @param lang the 2-digit language to match
+ * @return q-weight given for @a lang in @a language_pattern, 1.0 if no weights are given;
+ *         0 if @a lang is not in @a language_pattern
+ */
+double
+TALER_language_matches (const char *language_pattern,
+                        const char *lang)
+{
+  char *p = GNUNET_strdup (language_pattern);
+  char *sptr;
+  double r = 0.0;
+
+  for (char *tok = strtok_r (p, ",", &sptr);
+       NULL != tok;
+       tok = strtok_r (NULL, ",", &sptr))
+  {
+    char *sptr2;
+    char *lp = strtok_r (tok, ";", &sptr2);
+    char *qp = strtok_r (NULL, ";", &sptr2);
+    double q = 1.0;
+
+    while (isspace ((int) *lp))
+      lp++;
+    if (NULL != qp)
+      while (isspace ((int) *qp))
+        qp++;
+    GNUNET_break_op ( (NULL == qp) ||
+                      (1 == sscanf (qp,
+                                    "q=%lf",
+                                    &q)) );
+    if (0 == strcasecmp (lang,
+                         lp))
+      r = GNUNET_MAX (r, q);
+  }
+  GNUNET_free (p);
+  return r;
+}
+
+
+/* end of lang.c */