src/scripting/python/hooks.c

   1 /* Python scripting hooks */
   2
   3 #ifdef HAVE_CONFIG_H
   4 #include "config.h"
   5 #endif
   6
   7 #include <Python.h>
   8
   9 #include <stdarg.h>
  10 #include <string.h>
  11
  12 #include "elinks.h"
  13
  14 #include "cache/cache.h"
  15 #include "main/event.h"
  16 #include "protocol/uri.h"
  17 #include "scripting/python/core.h"
  18 #include "session/session.h"
  19 #include "util/memory.h"
  20 #include "util/string.h"
  21
  22 extern PyObject *python_hooks;
  23
  24 /*
  25  * A utility function for script_hook_url() and script_hook_get_proxy():
  26  * Free a char * and replace it with the contents of a Python string.
  27  * (Py_None is ignored.)
  28  */
  29
  30 static PyObject *
  31 replace_with_python_string(unsigned char **dest, PyObject *object)
  32 {
  33         unsigned char *str;
  34
  35         if (object == Py_None) return object;
  36
  37         str = (unsigned char *) PyString_AsString(object);
  38         if (!str) return NULL;
  39
  40         str = stracpy(str);
  41         if (!str) return PyErr_NoMemory();
  42
  43         mem_free_set(dest, str);
  44         return object;
  45 }
  46
  47 /* Call a Python hook for a goto-url or follow-url event. */
  48
  49 static enum evhook_status
  50 script_hook_url(va_list ap, void *data)
  51 {
  52         unsigned char **url = va_arg(ap, unsigned char **);
  53         struct session *ses = va_arg(ap, struct session *);
  54         char *method = data;
  55         struct session *saved_python_ses = python_ses;
  56         PyObject *result;
  57
  58         evhook_use_params(url && ses);
  59
  60         if (!python_hooks || !url || !*url
  61             || !PyObject_HasAttrString(python_hooks, method))
  62                 return EVENT_HOOK_STATUS_NEXT;
  63
  64         python_ses = ses;
  65
  66         result = PyObject_CallMethod(python_hooks, method, "s", *url);
  67
  68         if (!result || !replace_with_python_string(url, result))
  69                 alert_python_error();
  70
  71         Py_XDECREF(result);
  72
  73         python_ses = saved_python_ses;
  74
  75         return EVENT_HOOK_STATUS_NEXT;
  76 }
  77
  78 /* Call a Python hook for a pre-format-html event. */
  79
  80 static enum evhook_status
  81 script_hook_pre_format_html(va_list ap, void *data)
  82 {
  83         struct session *ses = va_arg(ap, struct session *);
  84         struct cache_entry *cached = va_arg(ap, struct cache_entry *);
  85         struct fragment *fragment = get_cache_fragment(cached);
  86         unsigned char *url = struri(cached->uri);
  87         char *method = "pre_format_html_hook";
  88         struct session *saved_python_ses = python_ses;
  89         PyObject *result;
  90         int success = 0;
  91
  92         evhook_use_params(ses && cached);
  93
  94         if (!python_hooks || !cached->length || !*fragment->data
  95             || !PyObject_HasAttrString(python_hooks, method))
  96                 return EVENT_HOOK_STATUS_NEXT;
  97
  98         python_ses = ses;
  99
 100         result = PyObject_CallMethod(python_hooks, method, "ss#", url,
 101                                      fragment->data, fragment->length);
 102         if (!result) goto error;
 103
 104         if (result != Py_None) {
 105                 unsigned char *str;
 106                 Py_ssize_t len;
 107
 108                 if (PyString_AsStringAndSize(result, (char **) &str, &len) != 0)
 109                         goto error;
 110
 111                 /* This assumes the Py_ssize_t len is not too large to
 112                  * fit in the off_t parameter of normalize_cache_entry().
 113                  * add_fragment() itself seems to assume the same thing,
 114                  * and there is no standard OFF_MAX macro against which
 115                  * ELinks could check the value.  */
 116                 (void) add_fragment(cached, 0, str, len);
 117                 normalize_cache_entry(cached, len);
 118         }
 119
 120         success = 1;
 121
 122 error:
 123         if (!success) alert_python_error();
 124
 125         Py_XDECREF(result);
 126
 127         python_ses = saved_python_ses;
 128
 129         return EVENT_HOOK_STATUS_NEXT;
 130 }
 131
 132 /* Call a Python hook for a get-proxy event. */
 133
 134 static enum evhook_status
 135 script_hook_get_proxy(va_list ap, void *data)
 136 {
 137         unsigned char **proxy = va_arg(ap, unsigned char **);
 138         unsigned char *url = va_arg(ap, unsigned char *);
 139         char *method = "proxy_for_hook";
 140         PyObject *result;
 141
 142         evhook_use_params(proxy && url);
 143
 144         if (!python_hooks || !proxy || !url
 145             || !PyObject_HasAttrString(python_hooks, method))
 146                 return EVENT_HOOK_STATUS_NEXT;
 147
 148         result = PyObject_CallMethod(python_hooks, method, "s", url);
 149
 150         if (!result || !replace_with_python_string(proxy, result))
 151                 alert_python_error();
 152
 153         Py_XDECREF(result);
 154
 155         return EVENT_HOOK_STATUS_NEXT;
 156 }
 157
 158 /* Call a Python hook for a quit event. */
 159
 160 static enum evhook_status
 161 script_hook_quit(va_list ap, void *data)
 162 {
 163         char *method = "quit_hook";
 164         PyObject *result;
 165
 166         if (!python_hooks || !PyObject_HasAttrString(python_hooks, method))
 167                 return EVENT_HOOK_STATUS_NEXT;
 168
 169         result = PyObject_CallMethod(python_hooks, method, NULL);
 170         if (!result) alert_python_error();
 171
 172         Py_XDECREF(result);
 173
 174         return EVENT_HOOK_STATUS_NEXT;
 175 }
 176
 177 struct event_hook_info python_scripting_hooks[] = {
 178         { "goto-url", 0, script_hook_url, "goto_url_hook" },
 179         { "follow-url", 0, script_hook_url, "follow_url_hook" },
 180         { "pre-format-html", 0, script_hook_pre_format_html, NULL },
 181         { "get-proxy", 0, script_hook_get_proxy, NULL },
 182         { "quit", 0, script_hook_quit, NULL },
 183         NULL_EVENT_HOOK_INFO,
 184 };