Basis.getenv

19 files changed, 143 insertions, 4 deletions

diff --git a/doc/manual.tex b/doc/manual.tex
index 0b8f1c06..8944dcfd 100644
--- a/doc/manual.tex
+++ b/doc/manual.tex
@@ -135,7 +135,7 @@ For each entry \texttt{M} in the module list, the file \texttt{M.urs} is include
 
 Here is the complete list of directive forms.  ``FFI'' stands for ``foreign function interface,'' Ur's facility for interaction between Ur programs and C and JavaScript libraries.
 \begin{itemize}
-\item \texttt{[allow|deny] [url|mime|requestHeader|responseHeader] PATTERN} registers a rule governing which URLs, MIME types, HTTP request headers, or HTTP response headers are allowed to appear explicitly in this application.  The first such rule to match a name determines the verdict.  If \texttt{PATTERN} ends in \texttt{*}, it is interpreted as a prefix rule.  Otherwise, a string must match it exactly.
+\item \texttt{[allow|deny] [url|mime|requestHeader|responseHeader|env] PATTERN} registers a rule governing which URLs, MIME types, HTTP request headers, HTTP response headers, or environment variable names are allowed to appear explicitly in this application.  The first such rule to match a name determines the verdict.  If \texttt{PATTERN} ends in \texttt{*}, it is interpreted as a prefix rule.  Otherwise, a string must match it exactly.
 \item \texttt{alwaysInline PATH} requests that every call to the referenced function be inlined.  Section \ref{structure} explains how functions are assigned path strings.
 \item \texttt{benignEffectful Module.ident} registers an FFI function or transaction as having side effects.  The optimizer avoids removing, moving, or duplicating calls to such functions.  Every effectful FFI function must be registered, or the optimizer may make invalid transformations.  This version of the \texttt{effectful} directive registers that this function only has side effects that remain local to a single page generation.
 \item \texttt{clientOnly Module.ident} registers an FFI function or transaction that may only be run in client browsers.
@@ -1469,7 +1469,7 @@ $$\begin{array}{l}
   \mt{val} \; \mt{fileData} : \mt{file} \to \mt{blob}
 \end{array}$$
 
-It is also possible to get HTTP request headers and set HTTP response headers, using abstract types similar to the one for URLs.
+It is also possible to get HTTP request headers and environment variables, and set HTTP response headers, using abstract types similar to the one for URLs.
 
 $$\begin{array}{l}
   \mt{type} \; \mt{requestHeader} \\
@@ -1477,6 +1477,11 @@ $$\begin{array}{l}
   \mt{val} \; \mt{checkRequestHeader} : \mt{string} \to \mt{option} \; \mt{requestHeader} \\
   \mt{val} \; \mt{getHeader} : \mt{requestHeader} \to \mt{transaction} \; (\mt{option} \; \mt{string}) \\
   \\
+  \mt{type} \; \mt{envVar} \\
+  \mt{val} \; \mt{blessEnvVar} : \mt{string} \to \mt{envVar} \\
+  \mt{val} \; \mt{checkEnvVar} : \mt{string} \to \mt{option} \; \mt{envVar} \\
+  \mt{val} \; \mt{getenv} : \mt{envVar} \to \mt{transaction} \; (\mt{option} \; \mt{string}) \\
+  \\
   \mt{type} \; \mt{responseHeader} \\
   \mt{val} \; \mt{blessResponseHeader} : \mt{string} \to \mt{responseHeader} \\
   \mt{val} \; \mt{checkResponseHeader} : \mt{string} \to \mt{option} \; \mt{responseHeader} \\
diff --git a/include/urweb/types.h b/include/urweb/types.h
index be7edb32..4b57ae0d 100644
--- a/include/urweb/types.h
+++ b/include/urweb/types.h
@@ -97,6 +97,7 @@ typedef struct {
   int (*check_mime)(const char *);
   int (*check_requestHeader)(const char *);
   int (*check_responseHeader)(const char *);
+  int (*check_envVar)(const char *);
 
   void (*on_error)(uw_context, char *);
 
diff --git a/include/urweb/urweb.h b/include/urweb/urweb.h
index af0aafdb..38efa20c 100644
--- a/include/urweb/urweb.h
+++ b/include/urweb/urweb.h
@@ -35,6 +35,7 @@ char *uw_get_url_prefix(uw_context);
 failure_kind uw_begin_init(uw_context);
 void uw_set_on_success(char *);
 void uw_set_headers(uw_context, char *(*get_header)(void *, const char *), void *get_header_data);
+void uw_set_env(uw_context, char *(*get_env)(void *, const char *), void *get_env_data);
 failure_kind uw_begin(uw_context, char *path);
 failure_kind uw_begin_onError(uw_context, char *msg);
 void uw_login(uw_context);
@@ -220,14 +221,17 @@ uw_Basis_string uw_Basis_bless(uw_context, uw_Basis_string);
 uw_Basis_string uw_Basis_blessMime(uw_context, uw_Basis_string);
 uw_Basis_string uw_Basis_blessRequestHeader(uw_context, uw_Basis_string);
 uw_Basis_string uw_Basis_blessResponseHeader(uw_context, uw_Basis_string);
+uw_Basis_string uw_Basis_blessEnvVar(uw_context, uw_Basis_string);
 
 uw_Basis_string uw_Basis_checkUrl(uw_context, uw_Basis_string);
 uw_Basis_string uw_Basis_checkMime(uw_context, uw_Basis_string);
 uw_Basis_string uw_Basis_checkRequestHeader(uw_context, uw_Basis_string);
 uw_Basis_string uw_Basis_checkResponseHeader(uw_context, uw_Basis_string);
+uw_Basis_string uw_Basis_checkEnvVar(uw_context, uw_Basis_string);
 
 uw_Basis_string uw_Basis_getHeader(uw_context, uw_Basis_string name);
 uw_unit uw_Basis_setHeader(uw_context, uw_Basis_string name, uw_Basis_string value);
+uw_Basis_string uw_Basis_getenv(uw_context, uw_Basis_string name);
 
 uw_Basis_string uw_unnull(uw_Basis_string);
 uw_Basis_string uw_Basis_makeSigString(uw_context, uw_Basis_string);
diff --git a/lib/ur/basis.urs b/lib/ur/basis.urs
index 101f8e63..4777be81 100644
--- a/lib/ur/basis.urs
+++ b/lib/ur/basis.urs
@@ -191,6 +191,11 @@ val blessResponseHeader : string -> responseHeader
 val checkResponseHeader : string -> option responseHeader
 val setHeader : responseHeader -> string -> transaction unit
 
+type envVar
+val blessEnvVar : string -> envVar
+val checkEnvVar : string -> option envVar
+val getenv : envVar -> transaction (option string)
+
 
 (** JavaScript-y gadgets *)
 
diff --git a/src/c/cgi.c b/src/c/cgi.c
index 6d6e5252..d3ec32c7 100644
--- a/src/c/cgi.c
+++ b/src/c/cgi.c
@@ -1,6 +1,7 @@
 #include "config.h"
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <ctype.h>
 #include <string.h>
 #include <stdlib.h>
@@ -39,6 +40,10 @@ static char *get_header(void *data, const char *h) {
     return NULL;
 }
 
+static char *get_env(void *data, const char *name) {
+  return getenv(name);
+}
+
 static void on_success(uw_context ctx) { }
 
 static void on_failure(uw_context ctx) {
@@ -102,6 +107,7 @@ int main(int argc, char *argv[]) {
 
   uw_set_on_success("");
   uw_set_headers(ctx, get_header, NULL);
+  uw_set_env(ctx, get_env, NULL);
   uw_request_init(&uw_application, NULL, log_error, log_debug);
 
   body[body_pos] = 0;
diff --git a/src/c/fastcgi.c b/src/c/fastcgi.c
index 5677af83..9e3c8d7e 100644
--- a/src/c/fastcgi.c
+++ b/src/c/fastcgi.c
@@ -229,6 +229,12 @@ static char *get_header(void *data, const char *h) {
   return search_nvps(hs->nvps, hs->uppercased);
 }
 
+static char *get_env(void *data, const char *h) {
+  headers *hs = (headers *)data;
+  
+  return search_nvps(hs->nvps, h);
+}
+
 static int read_funny_len(unsigned char **buf, int *len) {
   if (*len <= 0)
     return -1;
@@ -471,6 +477,7 @@ static void *worker(void *data) {
       query_string = "";
 
     uw_set_headers(ctx, get_header, &hs);
+    uw_set_env(ctx, get_env, &hs);
 
     {
       request_result rr;
diff --git a/src/c/http.c b/src/c/http.c
index 9af86070..aa045d7a 100644
--- a/src/c/http.c
+++ b/src/c/http.c
@@ -40,6 +40,10 @@ static char *get_header(void *data, const char *h) {
   return NULL;
 }
 
+static char *get_env(void *data, const char *name) {
+  return getenv(name);
+}
+
 static void on_success(uw_context ctx) {
   uw_write_header(ctx, "HTTP/1.1 200 OK\r\n");
 }
@@ -193,6 +197,7 @@ static void *worker(void *data) {
         }
 
         uw_set_headers(ctx, get_header, headers);
+        uw_set_env(ctx, get_env, NULL);
 
         printf("Serving URI %s....\n", path);
         rr = uw_request(rc, ctx, method, path, query_string, body, back - body,
diff --git a/src/c/urweb.c b/src/c/urweb.c
index 8d44088d..2eb1c9fe 100644
--- a/src/c/urweb.c
+++ b/src/c/urweb.c
@@ -420,6 +420,9 @@ struct uw_context {
   char *(*get_header)(void *, const char *);
   void *get_header_data;
 
+  char *(*get_env)(void *, const char *);
+  void *get_env_data;
+
   uw_buffer outHeaders, page, heap, script;
   int allowed_to_return_indirectly, returning_indirectly;
   input *inputs, *subinputs, *cur_container;
@@ -484,6 +487,9 @@ uw_context uw_init(int id, void *logger_data, uw_logger log_debug) {
   ctx->get_header = NULL;
   ctx->get_header_data = NULL;
 
+  ctx->get_env = NULL;
+  ctx->get_env_data = NULL;
+
   uw_buffer_init(uw_headers_max, &ctx->outHeaders, 1);
   ctx->outHeaders.start[0] = 0;
   uw_buffer_init(uw_page_max, &ctx->page, 1);
@@ -655,6 +661,11 @@ void uw_set_headers(uw_context ctx, char *(*get_header)(void *, const char *), v
   ctx->get_header_data = get_header_data;
 }
 
+void uw_set_env(uw_context ctx, char *(*get_env)(void *, const char *), void *get_env_data) {
+  ctx->get_env = get_env;
+  ctx->get_env_data = get_env_data;
+}
+
 static void uw_set_error(uw_context ctx, const char *fmt, ...) {
   va_list ap;
   va_start(ap, fmt);
@@ -3476,8 +3487,16 @@ uw_Basis_string uw_Basis_blessResponseHeader(uw_context ctx, uw_Basis_string s)
     uw_error(ctx, FATAL, "Disallowed response header %s", uw_Basis_htmlifyString(ctx, s));
 }
 
+static int envVar_format(const char *s) {
+  for (; *s; ++s)
+    if (!isalnum((int)*s) && *s != '_' && *s != '.')
+      return 0;
+
+  return 1;
+}
+
 uw_Basis_string uw_Basis_checkResponseHeader(uw_context ctx, uw_Basis_string s) {
-  if (!mime_format(s))
+  if (!envVar_format(s))
     return NULL;
 
   if (ctx->app->check_responseHeader(s))
@@ -3486,6 +3505,26 @@ uw_Basis_string uw_Basis_checkResponseHeader(uw_context ctx, uw_Basis_string s)
     return NULL;
 }
 
+uw_Basis_string uw_Basis_blessEnvVar(uw_context ctx, uw_Basis_string s) {
+  if (!envVar_format(s))
+    uw_error(ctx, FATAL, "Environment variable \"%s\" contains invalid character", uw_Basis_htmlifyString(ctx, s));
+
+  if (ctx->app->check_envVar(s))
+    return s;
+  else
+    uw_error(ctx, FATAL, "Disallowed environment variable %s", uw_Basis_htmlifyString(ctx, s));
+}
+
+uw_Basis_string uw_Basis_checkEnvVar(uw_context ctx, uw_Basis_string s) {
+  if (!mime_format(s))
+    return NULL;
+
+  if (ctx->app->check_envVar(s))
+    return s;
+  else
+    return NULL;
+}
+
 uw_Basis_string uw_Basis_getHeader(uw_context ctx, uw_Basis_string name) {
   return uw_Basis_requestHeader(ctx, name);
 }
@@ -3510,6 +3549,10 @@ uw_unit uw_Basis_setHeader(uw_context ctx, uw_Basis_string name, uw_Basis_string
   return uw_unit_v;
 }
 
+uw_Basis_string uw_Basis_getenv(uw_context ctx, uw_Basis_string name) {
+  return ctx->get_env(ctx->get_env_data, name);
+}
+
 uw_Basis_string uw_unnull(uw_Basis_string s) {
   return s ? s : "";
 }
diff --git a/src/cjr_print.sml b/src/cjr_print.sml
index c7be5526..c1198ccf 100644
--- a/src/cjr_print.sml
+++ b/src/cjr_print.sml
@@ -3380,6 +3380,9 @@ fun p_file env (ds, ps) =
 
              makeChecker ("uw_check_responseHeader", Settings.getResponseHeaderRules ()),
              newline,
+
+             makeChecker ("uw_check_envVar", Settings.getEnvVarRules ()),
+             newline,
              
              string "extern void uw_sign(const char *in, char *out);",
              newline,
@@ -3537,7 +3540,7 @@ fun p_file env (ds, ps) =
                          "uw_client_init", "uw_initializer", "uw_expunger",
                          "uw_db_init", "uw_db_begin", "uw_db_commit", "uw_db_rollback", "uw_db_close",
                          "uw_handle",
-                         "uw_input_num", "uw_cookie_sig", "uw_check_url", "uw_check_mime", "uw_check_requestHeader", "uw_check_responseHeader",
+                         "uw_input_num", "uw_cookie_sig", "uw_check_url", "uw_check_mime", "uw_check_requestHeader", "uw_check_responseHeader", "uw_check_envVar",
                          case onError of NONE => "NULL" | SOME _ => "uw_onError", "my_periodics",
                          "\"" ^ Prim.toCString (Settings.getTimeFormat ()) ^ "\""],
              string "};",
diff --git a/src/compiler.sig b/src/compiler.sig
index 2a900d41..f23728f0 100644
--- a/src/compiler.sig
+++ b/src/compiler.sig
@@ -54,6 +54,7 @@ signature COMPILER = sig
          filterMime : Settings.rule list,
          filterRequest : Settings.rule list,
          filterResponse : Settings.rule list,
+         filterEnv : Settings.rule list,
          protocol : string option,
          dbms : string option,
          sigFile : string option,
diff --git a/src/compiler.sml b/src/compiler.sml
index 10b2bd2f..a9720cf6 100644
--- a/src/compiler.sml
+++ b/src/compiler.sml
@@ -58,6 +58,7 @@ type job = {
      filterMime : Settings.rule list,
      filterRequest : Settings.rule list,
      filterResponse : Settings.rule list,
+     filterEnv : Settings.rule list,
      protocol : string option,
      dbms : string option,
      sigFile : string option,
@@ -365,6 +366,7 @@ fun institutionalizeJob (job : job) =
      Settings.setMimeRules (#filterMime job);
      Settings.setRequestHeaderRules (#filterRequest job);
      Settings.setResponseHeaderRules (#filterResponse job);
+     Settings.setEnvVarRules (#filterEnv job);
      Option.app Settings.setProtocol (#protocol job);
      Option.app Settings.setDbms (#dbms job);
      Settings.setSafeGets (#safeGets job);
@@ -439,6 +441,7 @@ fun parseUrp' accLibs fname =
                         filterMime = [],
                         filterRequest = [],
                         filterResponse = [],
+                        filterEnv = [],
                         protocol = NONE,
                         dbms = NONE,
                         sigFile = NONE,
@@ -557,6 +560,7 @@ fun parseUrp' accLibs fname =
                      val mime = ref []
                      val request = ref []
                      val response = ref []
+                     val env = ref []
                      val libs = ref []
                      val protocol = ref NONE
                      val dbms = ref NONE
@@ -592,6 +596,7 @@ fun parseUrp' accLibs fname =
                                  filterMime = rev (!mime),
                                  filterRequest = rev (!request),
                                  filterResponse = rev (!response),
+                                 filterEnv = rev (!env),
                                  sources = sources,
                                  protocol = !protocol,
                                  dbms = !dbms,
@@ -648,6 +653,7 @@ fun parseUrp' accLibs fname =
                                  filterMime = #filterMime old @ #filterMime new,
                                  filterRequest = #filterRequest old @ #filterRequest new,
                                  filterResponse = #filterResponse old @ #filterResponse new,
+                                 filterEnv = #filterEnv old @ #filterEnv new,
                                  sources = #sources new
                                            @ List.filter (fn s => List.all (fn s' => s' <> s) (#sources new))
                                                          (#sources old),
@@ -690,6 +696,7 @@ fun parseUrp' accLibs fname =
                            | "mime" => mime
                            | "requestHeader" => request
                            | "responseHeader" => response
+                           | "env" => env
                            | _ => (ErrorMsg.error "Bad filter kind";
                                    url)
 
diff --git a/src/demo.sml b/src/demo.sml
index 747bbd2c..26dcfa95 100644
--- a/src/demo.sml
+++ b/src/demo.sml
@@ -117,6 +117,7 @@ fun make' {prefix, dirname, guided} =
             filterMime = #filterMime combined @ #filterMime urp,
             filterRequest = #filterRequest combined @ #filterRequest urp,
             filterResponse = #filterResponse combined @ #filterResponse urp,
+            filterEnv = #filterEnv combined @ #filterEnv urp,
             protocol = mergeWith #2 (#protocol combined, #protocol urp),
             dbms = mergeWith #2 (#dbms combined, #dbms urp),
             sigFile = mergeWith #2 (#sigFile combined, #sigFile urp),
diff --git a/src/mono_opt.sml b/src/mono_opt.sml
index 70404c09..228c53e6 100644
--- a/src/mono_opt.sml
+++ b/src/mono_opt.sml
@@ -504,6 +504,17 @@ fun exp e =
              ESome ((TFfi ("Basis", "string"), loc), (se, loc))
          else
              ENone (TFfi ("Basis", "string"), loc))
+      | EFfiApp ("Basis", "blessEnvVar", [((se as EPrim (Prim.String s), loc), _)]) =>
+        (if Settings.checkEnvVar s then
+             ()
+         else
+             ErrorMsg.errorAt loc ("Invalid string " ^ s ^ " passed to 'blessEnvVar'");
+         se)
+      | EFfiApp ("Basis", "checkEnvVar", [((se as EPrim (Prim.String s), loc), _)]) =>
+        (if Settings.checkEnvVar s then
+             ESome ((TFfi ("Basis", "string"), loc), (se, loc))
+         else
+             ENone (TFfi ("Basis", "string"), loc))
 
       | EFfiApp ("Basis", "checkString", [((EPrim (Prim.String s), loc), _)]) => 
         let
diff --git a/src/monoize.sml b/src/monoize.sml
index 7b1da97a..371e1d43 100644
--- a/src/monoize.sml
+++ b/src/monoize.sml
@@ -225,6 +225,9 @@ fun monoType env =
                   | L.CFfi ("Basis", "css_property") => (L'.TFfi ("Basis", "string"), loc)
                   | L.CFfi ("Basis", "css_style") => (L'.TFfi ("Basis", "string"), loc)
                   | L.CFfi ("Basis", "id") => (L'.TFfi ("Basis", "string"), loc)
+                  | L.CFfi ("Basis", "requestHeader") => (L'.TFfi ("Basis", "string"), loc)
+                  | L.CFfi ("Basis", "responseHeader") => (L'.TFfi ("Basis", "string"), loc)
+                  | L.CFfi ("Basis", "envVar") => (L'.TFfi ("Basis", "string"), loc)
 
                   | L.CApp ((L.CFfi ("Basis", "serialized"), _), _) =>
                     (L'.TFfi ("Basis", "string"), loc)
diff --git a/src/settings.sig b/src/settings.sig
index a9ad36a5..3e3f0985 100644
--- a/src/settings.sig
+++ b/src/settings.sig
@@ -120,6 +120,10 @@ signature SETTINGS = sig
     val getResponseHeaderRules : unit -> rule list
     val checkResponseHeader : string -> bool
 
+    val setEnvVarRules : rule list -> unit
+    val getEnvVarRules : unit -> rule list
+    val checkEnvVar : string -> bool
+
     (* Web protocols that generated programs may speak *)
     type protocol = {
         name : string,       (* Call it this on the command line *)
diff --git a/src/settings.sml b/src/settings.sml
index 6712925f..45e8640a 100644
--- a/src/settings.sml
+++ b/src/settings.sml
@@ -400,16 +400,19 @@ val url = ref ([] : rule list)
 val mime = ref ([] : rule list)
 val request = ref ([] : rule list)
 val response = ref ([] : rule list)
+val env = ref ([] : rule list)
 
 fun setUrlRules ls = url := ls
 fun setMimeRules ls = mime := ls
 fun setRequestHeaderRules ls = request := ls
 fun setResponseHeaderRules ls = response := ls
+fun setEnvVarRules ls = env := ls
 
 fun getUrlRules () = !url
 fun getMimeRules () = !mime
 fun getRequestHeaderRules () = !request
 fun getResponseHeaderRules () = !response
+fun getEnvVarRules () = !env
 
 fun check f rules s =
     let
@@ -437,10 +440,12 @@ fun check f rules s =
 val checkUrl = check (fn _ => true) url
 
 val validMime = CharVector.all (fn ch => Char.isAlphaNum ch orelse ch = #"/" orelse ch = #"-" orelse ch = #".")
+val validEnv = CharVector.all (fn ch => Char.isAlphaNum ch orelse ch = #"_" orelse ch = #".")
 
 val checkMime = check validMime mime
 val checkRequestHeader = check validMime request
 val checkResponseHeader = check validMime response
+val checkEnvVar = check validEnv env
 
 
 type protocol = {
diff --git a/tests/env.ur b/tests/env.ur
new file mode 100644
index 00000000..637ea6b8
--- /dev/null
+++ b/tests/env.ur
@@ -0,0 +1,21 @@
+fun handler r =
+  vo <- getenv (blessEnvVar r.Nam);
+  return <xml><body>
+  {case vo of
+       None => <xml>Not set</xml>
+     | Some v => <xml>Set to: {[v]}</xml>}
+</body></xml>
+
+fun main () : transaction page =
+  term <- getenv (blessEnvVar "TERM");
+  return <xml><body>
+    TERM = {case term of
+                None => <xml>Nada</xml>
+              | Some v => txt v}
+                 
+    <form>
+      What would you like to know?
+      <textbox{#Nam}/>
+      <submit action={handler}/>
+    </form>
+  </body></xml>
diff --git a/tests/env.urp b/tests/env.urp
new file mode 100644
index 00000000..0860c8d7
--- /dev/null
+++ b/tests/env.urp
@@ -0,0 +1,6 @@
+rewrite url Env/*
+allow env TERM
+allow env DESKTOP_*
+allow env SCRIPT_NAME
+
+env
diff --git a/tests/env.urs b/tests/env.urs
new file mode 100644
index 00000000..6ac44e0b
--- /dev/null
+++ b/tests/env.urs
@@ -0,0 +1 @@
+val main : unit -> transaction page