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/location.h"
  19 #include "session/session.h"
  20 #include "util/memory.h"
  21 #include "util/string.h"
  22
  23 extern PyObject *python_hooks;
  24
  25 /*
  26  * A utility function for script_hook_url() and script_hook_get_proxy():
  27  * Free a char * and replace it with the contents of a Python string.
  28  * (Py_None is ignored.)
  29  */
  30
  31 static PyObject *
  32 replace_with_python_string(unsigned char **dest, PyObject *object)
  33 {
  34         unsigned char *str;
  35
  36         if (object == Py_None) return object;
  37
  38         str = (unsigned char *) PyString_AsString(object);
  39         if (!str) return NULL;
  40
  41         str = stracpy(str);
  42         if (!str) return PyErr_NoMemory();
  43
  44         mem_free_set(dest, str);
  45         return object;
  46 }
  47
  48 /* Call a Python hook for a goto-url or follow-url event. */
  49
  50 static enum evhook_status
  51 script_hook_url(va_list ap, void *data)
  52 {
  53         unsigned char **url = va_arg(ap, unsigned char **);
  54         struct session *ses = va_arg(ap, struct session *);
  55         char *method = data;
  56         struct session *saved_python_ses = python_ses;
  57         PyObject *result;
  58
  59         evhook_use_params(url && ses);
  60
  61         if (!python_hooks || !url || !*url
  62             || !PyObject_HasAttrString(python_hooks, method))
  63                 return EVENT_HOOK_STATUS_NEXT;
  64
  65         python_ses = ses;
  66
  67         /*
  68          * Historical note: The only reason the goto and follow hooks are
  69          * treated differently is to maintain backwards compatibility for
  70          * people who already have a goto_url_hook() function in hooks.py
  71          * that expects a second argument. If we were starting over from
  72          * scratch, we could treat the goto and follow hooks identically and
  73          * simply pass @url as the sole argument in both cases; the Python
  74          * code for the goto hook no longer needs its @current_url argument
  75          * since it could instead determine the current URL by calling the
  76          * Python interpreter's elinks.current_url() function.
  77          */
  78         if (!strcmp(method, "goto_url_hook")) {
  79                 unsigned char *current_url = NULL;
  80
  81                 if (python_ses && have_location(python_ses))
  82                         current_url = struri(cur_loc(ses)->vs.uri);
  83
  84                 result = PyObject_CallMethod(python_hooks, method, "ss", *url,
  85                                              current_url);
  86         } else {
  87                 result = PyObject_CallMethod(python_hooks, method, "s", *url);
  88         }
  89
  90         if (!result || !replace_with_python_string(url, result))
  91                 alert_python_error();
  92
  93         Py_XDECREF(result);
  94
  95         python_ses = saved_python_ses;
  96
  97         return EVENT_HOOK_STATUS_NEXT;
  98 }
  99
 100 /* Call a Python hook for a pre-format-html event. */
 101
 102 static enum evhook_status
 103 script_hook_pre_format_html(va_list ap, void *data)
 104 {
 105         struct session *ses = va_arg(ap, struct session *);
 106         struct cache_entry *cached = va_arg(ap, struct cache_entry *);
 107         struct fragment *fragment = get_cache_fragment(cached);
 108         unsigned char *url = struri(cached->uri);
 109         char *method = "pre_format_html_hook";
 110         struct session *saved_python_ses = python_ses;
 111         PyObject *result;
 112         int success = 0;
 113
 114         evhook_use_params(ses && cached);
 115
 116         if (!python_hooks || !cached->length || !*fragment->data
 117             || !PyObject_HasAttrString(python_hooks, method))
 118                 return EVENT_HOOK_STATUS_NEXT;
 119
 120         python_ses = ses;
 121
 122         result = PyObject_CallMethod(python_hooks, method, "ss#", url,
 123                                      fragment->data, fragment->length);
 124         if (!result) goto error;
 125
 126         if (result != Py_None) {
 127                 unsigned char *str;
 128                 int len;
 129
 130                 if (PyString_AsStringAndSize(result, (char **) &str, &len) != 0)
 131                         goto error;
 132
 133                 (void) add_fragment(cached, 0, str, len);
 134                 normalize_cache_entry(cached, len);
 135         }
 136
 137         success = 1;
 138
 139 error:
 140         if (!success) alert_python_error();
 141
 142         Py_XDECREF(result);
 143
 144         python_ses = saved_python_ses;
 145
 146         return EVENT_HOOK_STATUS_NEXT;
 147 }
 148
 149 /* Call a Python hook for a get-proxy event. */
 150
 151 static enum evhook_status
 152 script_hook_get_proxy(va_list ap, void *data)
 153 {
 154         unsigned char **proxy = va_arg(ap, unsigned char **);
 155         unsigned char *url = va_arg(ap, unsigned char *);
 156         char *method = "proxy_for_hook";
 157         PyObject *result;
 158
 159         evhook_use_params(proxy && url);
 160
 161         if (!python_hooks || !proxy || !url
 162             || !PyObject_HasAttrString(python_hooks, method))
 163                 return EVENT_HOOK_STATUS_NEXT;
 164
 165         result = PyObject_CallMethod(python_hooks, method, "s", url);
 166
 167         if (!result || !replace_with_python_string(proxy, result))
 168                 alert_python_error();
 169
 170         Py_XDECREF(result);
 171
 172         return EVENT_HOOK_STATUS_NEXT;
 173 }
 174
 175 /* Call a Python hook for a quit event. */
 176
 177 static enum evhook_status
 178 script_hook_quit(va_list ap, void *data)
 179 {
 180         char *method = "quit_hook";
 181         PyObject *result;
 182
 183         if (!python_hooks || !PyObject_HasAttrString(python_hooks, method))
 184                 return EVENT_HOOK_STATUS_NEXT;
 185
 186         result = PyObject_CallMethod(python_hooks, method, NULL);
 187         if (!result) alert_python_error();
 188
 189         Py_XDECREF(result);
 190
 191         return EVENT_HOOK_STATUS_NEXT;
 192 }
 193
 194 struct event_hook_info python_scripting_hooks[] = {
 195         { "goto-url", 0, script_hook_url, "goto_url_hook" },
 196         { "follow-url", 0, script_hook_url, "follow_url_hook" },
 197         { "pre-format-html", 0, script_hook_pre_format_html, NULL },
 198         { "get-proxy", 0, script_hook_get_proxy, NULL },
 199         { "quit", 0, script_hook_quit, NULL },
 200         NULL_EVENT_HOOK_INFO,
 201 };