--- a/src/c/openid.c	Sun Dec 26 12:04:08 2010 -0500
+++ b/src/c/openid.c	Sun Dec 26 13:10:36 2010 -0500
@@ -1,10 +1,108 @@
+#include <string.h>
+
 #include <openssl/sha.h>
 #include <curl/curl.h>
+#include <expat.h>
 
-#include <urweb/urweb.h>
+#include <openid.h>
 
 uw_unit uw_OpenidFfi_init(uw_context ctx) {
   curl_global_init(CURL_GLOBAL_ALL);
 
   return uw_unit_v;
 }
+
+static CURL *curl(uw_context ctx) {
+  CURL *r;
+
+  if (!(r = uw_get_global(ctx, "curl"))) {
+    r = curl_easy_init();
+    if (r)
+      uw_set_global(ctx, "curl", r, curl_easy_cleanup);
+  }
+
+  return r;
+}
+
+typedef struct {
+  uw_context ctx;
+  char *result;
+} endpoint;
+
+static void XMLCALL startElement(void *userData, const XML_Char *name, const XML_Char **atts) {
+  endpoint *ep = userData;
+
+  if (!strcmp(name, "link")) {
+    const XML_Char **attp;
+    int found = 0;
+
+    for (attp = atts; *attp; attp += 2) {
+      if (!strcmp(attp[0], "rel") && !strcmp(attp[1], "openid2.provider")) {
+        found = 1;
+        break;
+      }
+    }
+
+    if (found) {
+      for (attp = atts; *attp; attp += 2) {
+        if (!strcmp(attp[0], "href")) {
+          ep->result = uw_strdup(ep->ctx, attp[1]);
+          return;
+        }
+      }
+    }
+  }
+}
+
+static void XMLCALL endElement(void *userData, const XML_Char *name) {
+}
+
+typedef struct {
+  XML_Parser parser;
+  int any_errors;
+} curl_data;
+
+static size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp) {
+  curl_data *d = userp;
+
+  if (!XML_Parse(d->parser, buffer, size * nmemb, 0))
+    d->any_errors = 1;
+
+  return size * nmemb;
+}
+
+uw_Basis_string uw_OpenidFfi_discover(uw_context ctx, uw_Basis_string id) {
+  char *s;
+  CURL *c = curl(ctx);
+  curl_data cd = {};
+  endpoint ep = {ctx};
+  CURLcode code;
+
+  if (!strchr(id, ':')) {
+    id = uw_Basis_strcat(ctx, "http://", id);
+    if ((s = strchr(id, '#')) != NULL)
+      *s = 0;
+  } else if ((s = strchr(id, '#')) != NULL) {
+    char *id2 = uw_malloc(ctx, s - id + 1);
+    memcpy(id2, s, s - id);
+    id2[s - id] = 0;
+    id = id2;
+  }
+
+  cd.parser = XML_ParserCreate(NULL);
+  XML_SetUserData(cd.parser, &ep);
+  uw_push_cleanup(ctx, (void (*)(void *))XML_ParserFree, cd.parser);
+  XML_SetElementHandler(cd.parser, startElement, endElement);
+
+  curl_easy_setopt(c, CURLOPT_URL, id);
+  curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, write_data);
+  curl_easy_setopt(c, CURLOPT_WRITEDATA, &cd);
+
+  code = curl_easy_perform(c);
+  uw_pop_cleanup(ctx);
+
+  if (code)
+    return NULL;
+  else
+    return ep.result;
+}