added http_getter OCaml implementation

[helm.git] / helm / http_getter / http_getter_cache.ml

diff --git a/helm/http_getter/http_getter_cache.ml b/helm/http_getter/http_getter_cache.ml
new file mode 100644 (file)
index 0000000..6d2fe6e
--- /dev/null
+++ b/helm/http_getter/http_getter_cache.ml
@@ -0,0 +1,118 @@
+(*
+ *  Copyright (C) 2000, HELM Team.
+ *
+ *  This file is part of HELM, an Hypertextual, Electronic
+ *  Library of Mathematics, developed at the Computer Science
+ *  Department, University of Bologna, Italy.
+ *
+ *  HELM 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 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  HELM 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 HELM; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ *  MA  02111-1307, USA.
+ *
+ *  For details, see the HELM World-Wide-Web page,
+ *  http://cs.unibo.it/helm/.
+ *)
+
+open Http_getter_common;;
+open Http_getter_types;;
+open Printf;;
+
+let resource_type_of_url = function
+  | url when Pcre.pmatch ~pat:"\\.xml\\.gz$" url -> Enc_gzipped
+  | url when Pcre.pmatch ~pat:"\\.xml$" url -> Enc_normal
+  | url -> raise (Http_getter_invalid_URL url)
+let extension_of_resource_type = function
+  | Enc_normal -> "xml"
+  | Enc_gzipped -> "xml.gz"
+
+  (* basename = resource name without trailing ".gz", if any *)
+let is_in_cache basename =
+  Sys.file_exists
+    (match Http_getter_env.cache_mode with
+    | Enc_normal -> basename
+    | Enc_gzipped -> basename ^ ".gz")
+
+let respond_xml ?(enc = Enc_normal) ?(patch_dtd = true) ~url ~uri outchan =
+  let resource_type = resource_type_of_url url in
+  let extension = extension_of_resource_type resource_type in
+  let downloadname =
+    match http_getter_uri_of_string uri with
+    | Xml_uri (Cic baseuri) | Xml_uri (Theory baseuri) ->
+          (* assumption: baseuri starts with "/" *)
+        sprintf "%s%s.%s" Http_getter_env.xml_dir baseuri extension
+    | Rdf_uri (prefix, ((Cic baseuri) as qbaseuri))
+    | Rdf_uri (prefix, ((Theory baseuri) as qbaseuri)) ->
+        let escaped_prefix =
+          (Pcre.replace ~pat:"/" ~templ:"_"
+            (Pcre.replace ~pat:"_" ~templ:"__"
+              (prefix ^
+              (match qbaseuri with
+              | Cic _ -> "//cic:"
+              | Theory _ -> "//theory:"))))
+        in
+        sprintf "%s/%s%s.%s"
+          Http_getter_env.rdf_dir escaped_prefix baseuri extension
+  in
+  let patch_fun =
+    if patch_dtd then Http_getter_common.patch_xml else (fun x -> x)
+  in
+  let basename = Pcre.replace ~pat:"\\.gz$" downloadname in
+  if not (is_in_cache basename) then begin (* download and fill cache *)
+    wget ~output:downloadname url;
+    match (resource_type, Http_getter_env.cache_mode) with
+    | Enc_normal, Enc_normal ->
+        (if enc = Enc_gzipped then gzip ~keep:true downloadname)
+    | Enc_gzipped, Enc_gzipped ->
+        (if enc = Enc_normal then gunzip ~keep:true downloadname)
+    | Enc_normal, Enc_gzipped -> gzip ~keep:(enc = Enc_normal) downloadname
+    | Enc_gzipped, Enc_normal -> gunzip ~keep:(enc = Enc_gzipped) downloadname
+  end else begin  (* resource already in cache *)
+    match (enc, Http_getter_env.cache_mode) with
+    | Enc_normal, Enc_normal | Enc_gzipped, Enc_gzipped -> ()
+    | Enc_normal, Enc_gzipped -> gunzip ~keep:true (basename ^ ".gz")
+    | Enc_gzipped, Enc_normal -> gzip ~keep:true basename
+  end;  (* now resource is in cache *)
+  (* invariant: file to be sent back to client is available on disk in the
+  format the client likes *)
+  (match enc with  (* send file to client *)
+  | Enc_normal ->
+      return_file ~fname:basename ~contype:"text/xml" ~patch_fun outchan
+  | Enc_gzipped ->
+      return_file
+        ~fname:(basename ^ ".gz") ~contype:"text/xml"  ~contenc:"x-gzip"
+        ~patch_fun outchan);
+  match (enc, Http_getter_env.cache_mode) with  (* remove temp files *)
+  | Enc_normal, Enc_normal | Enc_gzipped, Enc_gzipped -> ()
+  | Enc_normal, Enc_gzipped -> Sys.remove basename
+  | Enc_gzipped, Enc_normal -> Sys.remove (basename ^ ".gz")
+
+  (* TODO enc is not yet supported *)
+let respond_xsl ?(enc = Enc_normal) ?(patch_dtd = true) ~url outchan =
+  let patch_fun =
+    if patch_dtd then Http_getter_common.patch_xsl else (fun x -> x)
+  in
+  let fname = tempfile () in
+  wget ~output:fname url;
+  return_file ~fname ~contype:"text/xml" ~patch_fun outchan;
+  Sys.remove fname
+
+  (* TODO patch_dtd and format are fooish, implement them! *)
+let respond_dtd ?(enc = Enc_normal) ?(patch_dtd = true) ~url outchan =
+    if Sys.file_exists url then
+      return_file
+        ~fname:url ~contype:"text/xml" ~patch_fun:Http_getter_common.patch_dtd
+        outchan
+    else
+      return_html_error ("Can't find DTD: " ^ url) outchan
+