diff --git a/assign.php b/assign.php
index 0e716059f..6509a488c 100644
--- a/assign.php
+++ b/assign.php
@@ -124,16 +124,18 @@ function pcAssignments($qreq) {
     }
 }
 
-if (isset($Qreq->update) && $Me->allow_administer($prow) && $Qreq->post_ok()) {
-    pcAssignments($Qreq);
-} else if (isset($Qreq->update) && $Qreq->ajax) {
-    json_exit(["ok" => false, "error" => "Only administrators can assign papers."]);
+if (isset($Qreq->update) && $Qreq->valid_post()) {
+    if ($Me->allow_administer($prow)) {
+        pcAssignments($Qreq);
+    } else if ($Qreq->ajax) {
+        json_exit(["ok" => false, "error" => "Only administrators can assign papers."]);
+    }
 }
 
 
 // add review requests
 if ((isset($Qreq->requestreview) || isset($Qreq->approvereview))
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $result = RequestReview_API::requestreview($Me, $Qreq, $prow);
     $result = JsonResult::make($result);
     if ($result->content["ok"]) {
@@ -158,7 +160,7 @@ function pcAssignments($qreq) {
 
 // deny review request
 if ((isset($Qreq->deny) || isset($Qreq->denyreview))
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $result = RequestReview_API::denyreview($Me, $Qreq, $prow);
     $result = JsonResult::make($result);
     if ($result->content["ok"]) {
@@ -173,7 +175,7 @@ function pcAssignments($qreq) {
 
 // retract review request
 if (isset($Qreq->retractreview)
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $result = RequestReview_API::retractreview($Me, $Qreq, $prow);
     $result = JsonResult::make($result);
     if ($result->content["ok"]) {
@@ -190,9 +192,9 @@ function pcAssignments($qreq) {
     }
 }
 
-// retract review request
+// remove declined review
 if (isset($Qreq->undeclinereview)
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $result = RequestReview_API::undeclinereview($Me, $Qreq, $prow);
     $result = JsonResult::make($result);
     if ($result->content["ok"]) {
diff --git a/autoassign.php b/autoassign.php
index 88dd0084d..d7fc308e9 100644
--- a/autoassign.php
+++ b/autoassign.php
@@ -13,7 +13,7 @@
 if (!isset($Qreq->q) || trim($Qreq->q) === "(All)") {
     $Qreq->q = "";
 }
-if ($Qreq->post_ok()) {
+if ($Qreq->valid_post()) {
     header("X-Accel-Buffering: no");  // NGINX: do not hold on to file
 }
 
@@ -60,7 +60,7 @@
     if ($Conf->setting("autoassign_badpairs")) {
         $Qreq->badpairs = 1;
     }
-} else if ($Me->privChair && isset($Qreq->assign) && $Qreq->post_ok()) {
+} else if ($Me->privChair && isset($Qreq->assign) && $Qreq->valid_post()) {
     $x = array();
     for ($i = 1; isset($Qreq["bpa$i"]); ++$i) {
         if ($Qreq["bpa$i"]
@@ -150,7 +150,7 @@ function sanitize_qreq_redirect($qreq) {
 if ($Qreq->saveassignment
     && $Qreq->submit
     && isset($Qreq->assignment)
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $assignset = new AssignmentSet($Me, true);
     $assignset->enable_papers($SSel->selection());
     $assignset->parse($Qreq->assignment);
@@ -546,7 +546,7 @@ function echo_result() {
     '<div class="papmode"><a href="', $Conf->hoturl("bulkassign"), '">Bulk update</a></div>',
     '</div><hr class="c">';
 
-if (isset($Qreq->a) && isset($Qreq->pctyp) && $Qreq->post_ok()) {
+if (isset($Qreq->a) && isset($Qreq->pctyp) && $Qreq->valid_post()) {
     if (isset($Qreq->assignment) && isset($Qreq->showassignment)) {
         $ai = new AutoassignerInterface($Me, $Qreq, $SSel);
         $ai->echo_result();
diff --git a/bulkassign.php b/bulkassign.php
index 76bf789de..1089935b3 100644
--- a/bulkassign.php
+++ b/bulkassign.php
@@ -12,7 +12,7 @@
 ]);
 
 $Qreq->rev_round = (string) $Conf->sanitize_round_name($Qreq->rev_round);
-if ($Qreq->post_ok()) {
+if ($Qreq->valid_post()) {
     header("X-Accel-Buffering: no");  // NGINX: do not hold on to file
 }
 
@@ -90,7 +90,7 @@ function complete_assignment($qreq, $callback) {
 
 // perform quick assignments all at once
 if (isset($Qreq->saveassignment)
-    && $Qreq->post_ok()
+    && $Qreq->valid_post()
     && isset($Qreq->file)
     && $Qreq->assignment_size_estimate < 1000
     && complete_assignment($Qreq, null)) {
@@ -112,7 +112,7 @@ function complete_assignment($qreq, $callback) {
     unset($Qreq->bulkentry);
 }
 if (isset($Qreq->upload)
-    && $Qreq->post_ok()
+    && $Qreq->valid_post()
     && ($Qreq->bulkentry || $Qreq->has_file("bulk"))) {
     flush();
     while (@ob_end_flush()) {
@@ -175,7 +175,7 @@ function complete_assignment($qreq, $callback) {
 }
 
 if (isset($Qreq->saveassignment)
-    && $Qreq->post_ok()
+    && $Qreq->valid_post()
     && isset($Qreq->file)
     && $Qreq->assignment_size_estimate >= 1000) {
     complete_assignment($Qreq, "keep_browser_alive");
diff --git a/buzzer.php b/buzzer.php
index d82f55596..2ac50a284 100644
--- a/buzzer.php
+++ b/buzzer.php
@@ -36,7 +36,7 @@ function kiosk_manager(Contact $user, Qrequest $qreq) {
         $user->conf->save_setting("__tracker_kiosk", 1, $kiosks);
     }
     // maybe sign out to kiosk
-    if ($qreq->signout_to_kiosk && $qreq->post_ok()) {
+    if ($qreq->signout_to_kiosk && $qreq->valid_post()) {
         $user = LoginHelper::logout($user, false);
         ensure_session(ENSURE_SESSION_REGENERATE_ID);
         $key = $kiosk_keys[$qreq->buzzer_showpapers ? 1 : 0];
diff --git a/checkupdates.php b/checkupdates.php
index c695500e7..8d9e8d771 100644
--- a/checkupdates.php
+++ b/checkupdates.php
@@ -5,7 +5,10 @@
 require_once("src/initweb.php");
 header("Content-Type: " . ($Qreq->text ? "text/plain" : "application/json"));
 
-if ($Me->privChair && $Qreq->post_ok() && isset($Qreq->ignore)) {
+if ($Me->privChair
+    && $Qreq->valid_token()
+    && !$Qreq->is_head()
+    && isset($Qreq->ignore)) {
     $when = time() + 86400 * 2;
     $Conf->qe("insert into Settings (name, value) values (?, ?) on duplicate key update value=?", "ignoreupdate_" . $Qreq->ignore, $when, $when);
 }
diff --git a/index.php b/index.php
index 4274045d1..3b6fc2ed2 100644
--- a/index.php
+++ b/index.php
@@ -30,7 +30,7 @@ function gx_call_requests(Conf $conf, Contact $user, Qrequest $qreq, $group, Gro
             $not_allowed = true;
         }
     }
-    if ($not_allowed && $qreq->method() === "POST" && !$qreq->post_ok()) {
+    if ($not_allowed && $qreq->is_post() && !$qreq->valid_token()) {
         $conf->msg($conf->_i("badpost"), 2);
     }
     foreach ($reqgj as $gj) {
diff --git a/lib/login.php b/lib/login.php
index d6b5b6c80..2b0af266b 100644
--- a/lib/login.php
+++ b/lib/login.php
@@ -72,7 +72,7 @@ static private function user_lookup(Conf $conf, Qrequest $qreq) {
 
     static function login_info(Conf $conf, Qrequest $qreq) {
         assert(!$conf->external_login());
-        assert($qreq->post_ok());
+        assert($qreq->valid_post());
 
         $user = self::user_lookup($conf, $qreq);
         if (is_array($user)) {
@@ -213,7 +213,7 @@ static function check_postlogin(Contact $user, Qrequest $qreq) {
 
     static function new_account_info(Conf $conf, Qrequest $qreq) {
         assert($conf->allow_user_self_register());
-        assert($qreq->post_ok());
+        assert($qreq->valid_post());
 
         $user = self::user_lookup($conf, $qreq);
         if (is_array($user)) {
diff --git a/lib/qrequest.php b/lib/qrequest.php
index 5be4cca1f..50045c345 100644
--- a/lib/qrequest.php
+++ b/lib/qrequest.php
@@ -43,6 +43,10 @@ function is_get() {
     function is_post() {
         return $this->____method === "POST";
     }
+    /** @return bool */
+    function is_head() {
+        return $this->____method === "HEAD";
+    }
     /** @return ?string */
     function page() {
         return $this->____page;
@@ -287,13 +291,30 @@ function checked_annex($name, $class) {
     function set_annex($name, $x) {
         $this->____x[$name] = $x;
     }
-    function approve_post() {
+    /** @return void */
+    function approve_token() {
         $this->____post_ok = true;
     }
     /** @return bool */
+    function valid_token() {
+        return $this->____post_ok;
+    }
+    /** @deprecated
+     * @return bool */
     function post_ok() {
+        if ($this->____post_ok && $this->____method !== "POST") {
+            error_log("Qrequest::post_ok() on {$this->____method}");
+        }
         return $this->____post_ok;
     }
+    /** @return bool */
+    function valid_post() {
+        if ($this->____post_ok && $this->____method !== "POST") {
+            error_log("Qrequest::valid_post() on {$this->____method}");
+        }
+        return $this->____post_ok && $this->____method === "POST";
+    }
+    /** @return void */
     function set_post_empty() {
         $this->____post_empty = true;
     }
@@ -304,12 +325,11 @@ function post_empty() {
 
     function xt_allow($e) {
         if ($e === "post") {
-            return $this->method() === "POST" && $this->post_ok();
+            return $this->____method === "POST" && $this->____post_ok;
         } else if ($e === "anypost") {
-            return $this->method() === "POST";
+            return $this->____method === "POST";
         } else if ($e === "getpost") {
-            return ($this->method() === "POST" || $this->method() === "GET")
-                && $this->post_ok();
+            return in_array($this->____method, ["POST", "GET", "HEAD"]) && $this->____post_ok;
         } else if (str_starts_with($e, "req.")) {
             foreach (explode(" ", $e) as $w) {
                 if (str_starts_with($w, "req.")
diff --git a/mail.php b/mail.php
index c1b34e0ad..3f68ab2d2 100644
--- a/mail.php
+++ b/mail.php
@@ -582,13 +582,14 @@ private function run() {
     && !$Qreq->psearch
     && !$Qreq->again
     && !$recip->error
-    && $Qreq->post_ok()) {
-    if ($Qreq->send && $Qreq->mailid)
+    && $Qreq->valid_post()) {
+    if ($Qreq->send && $Qreq->mailid) {
         MailSender::send2($Me, $recip, $Qreq);
-    else if ($Qreq->send)
+    } else if ($Qreq->send) {
         MailSender::send1($Me, $recip, $Qreq);
-    else if ($Qreq->check || $Qreq->group || $Qreq->ungroup)
+    } else if ($Qreq->check || $Qreq->group || $Qreq->ungroup) {
         MailSender::check($Me, $recip, $Qreq);
+    }
 }
 
 
diff --git a/manualassign.php b/manualassign.php
index ef7a7a007..19bf32e32 100644
--- a/manualassign.php
+++ b/manualassign.php
@@ -104,10 +104,12 @@ function saveAssignments($qreq, $reviewer) {
 }
 
 
-if ($Qreq->update && $reviewer && $Qreq->post_ok()) {
-    saveAssignments($Qreq, $reviewer);
-} else if ($Qreq->update) {
-    Conf::msg_error("You need to select a reviewer.");
+if ($Qreq->update && $Qreq->valid_post()) {
+    if ($reviewer) {
+        saveAssignments($Qreq, $reviewer);
+    } else {
+        Conf::msg_error("You need to select a reviewer.");
+    }
 }
 
 
diff --git a/mergeaccounts.php b/mergeaccounts.php
index fc8bc0743..d1738f42d 100644
--- a/mergeaccounts.php
+++ b/mergeaccounts.php
@@ -3,8 +3,9 @@
 // Copyright (c) 2006-2020 Eddie Kohler; see LICENSE.
 
 require_once("src/initweb.php");
-if (!$Me->email)
+if (!$Me->email) {
     $Me->escape();
+}
 $MergeError = "";
 
 function crpmerge($qreq, $MiniMe) {
@@ -45,7 +46,7 @@ function crpmerge($qreq, $MiniMe) {
     }
 }
 
-if (isset($Qreq->merge) && $Qreq->post_ok()) {
+if (isset($Qreq->merge) && $Qreq->valid_post()) {
     if (!$Qreq->email) {
         $MergeError = "Enter an email address to merge.";
         Ht::error_at("email");
diff --git a/offline.php b/offline.php
index 20bcc9b9c..6a03fd945 100644
--- a/offline.php
+++ b/offline.php
@@ -3,8 +3,9 @@
 // Copyright (c) 2006-2020 Eddie Kohler; see LICENSE.
 
 require_once("src/initweb.php");
-if (!$Me->email)
+if (!$Me->email) {
     $Me->escape();
+}
 $rf = $Conf->review_form();
 
 
@@ -26,7 +27,7 @@
 // upload review form action
 if (isset($Qreq->uploadForm)
     && $Qreq->has_file("uploadedFile")
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $tf = ReviewValues::make_text($rf, $Qreq->file_contents("uploadedFile"),
                         $Qreq->file_filename("uploadedFile"));
     while ($tf->parse_text($Qreq->override))
@@ -68,7 +69,7 @@ function setTagIndexes(Contact $user, $qreq) {
 }
 if ((isset($Qreq->setvote) || isset($Qreq->setrank))
     && $Me->is_reviewer()
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     setTagIndexes($Me, $Qreq);
 }
 
diff --git a/paper.php b/paper.php
index 9c3fae749..77a66df34 100644
--- a/paper.php
+++ b/paper.php
@@ -15,7 +15,7 @@
 if (isset($Qreq->p)
     && ctype_digit($Qreq->p)
     && !$Qreq->path()
-    && !$Qreq->post_ok()) {
+    && $Qreq->is_get()) {
     $Conf->redirect_self($Qreq);
 }
 if (!isset($Qreq->p)
@@ -42,7 +42,7 @@
 if ($Me->is_empty()) {
     $Me->escape();
 }
-if ($Qreq->post_ok() && !$Me->has_account_here()) {
+if ($Qreq->valid_token() && !$Me->has_account_here()) {
     if (isset($Qreq->update) && $Me->can_start_paper()) {
         $Me->activate_database_account();
     } else {
@@ -78,6 +78,14 @@ function errorMsgExit($msg) {
     Conf::$main->post_missing_msg();
 }
 
+// cancel action
+if ($Qreq->cancel) {
+    if ($prow && $prow->timeSubmitted && $Qreq->m === "edit") {
+        unset($Qreq->m);
+    }
+    $Conf->redirect_self($Qreq);
+}
+
 
 // grab paper row
 function loadRows() {
@@ -101,7 +109,7 @@ function loadRows() {
 
 
 // withdraw and revive actions
-if (isset($Qreq->withdraw) && $prow && $Qreq->post_ok()) {
+if (isset($Qreq->withdraw) && $prow && $Qreq->valid_post()) {
     if (!($whyNot = $Me->perm_withdraw_paper($prow))) {
         $reason = (string) $Qreq->reason;
         if ($reason === ""
@@ -142,7 +150,8 @@ function loadRows() {
         Conf::msg_error(whyNotText($whyNot) . " The submission has not been withdrawn.");
     }
 }
-if (isset($Qreq->revive) && $prow && $Qreq->post_ok()) {
+
+if (isset($Qreq->revive) && $prow && $Qreq->valid_post()) {
     if (!($whyNot = $Me->perm_revive_paper($prow))) {
         $aset = new AssignmentSet($Me, true);
         $aset->enable_papers($prow);
@@ -360,7 +369,7 @@ function update_paper(Qrequest $qreq, $action) {
 }
 
 
-if (($Qreq->update || $Qreq->submitfinal) && $Qreq->post_ok()) {
+if (($Qreq->update || $Qreq->submitfinal) && $Qreq->valid_post()) {
     // choose action
     $action = "update";
     if ($Qreq->submitfinal && $prow) {
@@ -387,7 +396,7 @@ function update_paper(Qrequest $qreq, $action) {
              && $Me->can_finalize_paper($prow));
 }
 
-if ($Qreq->updatecontacts && $Qreq->post_ok() && $prow) {
+if ($Qreq->updatecontacts && $Qreq->valid_post() && $prow) {
     if ($Me->can_administer($prow) || $Me->act_author_view($prow)) {
         $ps = new PaperStatus($Conf, $Me);
         if ($ps->prepare_save_paper_web($Qreq, $prow, "updatecontacts")) {
@@ -409,13 +418,13 @@ function update_paper(Qrequest $qreq, $action) {
     $useRequest = true;
 }
 
-if ($Qreq->updateoverride && $Qreq->post_ok() && $prow) {
+if ($Qreq->updateoverride && $Qreq->valid_post() && $prow) {
     $Conf->redirect_self($Qreq, ["p" => $prow->paperId, "m" => "edit", "forceShow" => 1]);
 }
 
 
 // delete action
-if ($Qreq->delete && $Qreq->post_ok()) {
+if ($Qreq->delete && $Qreq->valid_post()) {
     if (!$prow) {
         $Conf->confirmMsg("Submission deleted.");
     } else if (!$Me->can_administer($prow)) {
@@ -432,12 +441,6 @@ function update_paper(Qrequest $qreq, $action) {
         errorMsgExit("");
     }
 }
-if ($Qreq->cancel && $Qreq->post_ok()) {
-    if ($prow && $prow->timeSubmitted && $Qreq->m === "edit") {
-        unset($Qreq->m);
-    }
-    $Conf->redirect_self($Qreq);
-}
 
 
 // correct modes
diff --git a/profile.php b/profile.php
index e19422778..2da1a8137 100644
--- a/profile.php
+++ b/profile.php
@@ -42,7 +42,7 @@ function change_email_by_capability($Qreq) {
         if ($newcdbu->contactdb_disabled()) { // NB do not use is_disabled()
             Conf::msg_error("changeemail", "That user is globally disabled.");
             return false;
-        } else if ($Qreq->go && $Qreq->post_ok()) {
+        } else if ($Qreq->go && $Qreq->valid_post()) {
             $Qreq->password = trim((string) $Qreq->password);
             $info = $newcdbu->check_password_info($Qreq->password);
             if (!$info["ok"]) {
@@ -55,7 +55,7 @@ function change_email_by_capability($Qreq) {
 
     if ($newemail
         && $Qreq->go
-        && $Qreq->post_ok()) {
+        && $Qreq->valid_post()) {
         $Acct->change_email($newemail);
         $capdata->delete();
         $Conf->confirmMsg("Your email address has been changed.");
@@ -416,7 +416,7 @@ function parseBulkFile($text, $filename) {
     return empty($errors);
 }
 
-if (!$Qreq->post_ok()) {
+if (!$Qreq->valid_post()) {
     // do nothing
 } else if ($Qreq->savebulk && $newProfile && $Qreq->has_file("bulk")) {
     if (($text = $Qreq->file_contents("bulk")) === false) {
@@ -477,7 +477,7 @@ function parseBulkFile($text, $filename) {
     $Conf->redirect_hoturl("mergeaccounts");
 }
 
-if (isset($Qreq->delete) && !Dbl::has_error() && $Qreq->post_ok()) {
+if (isset($Qreq->delete) && !Dbl::has_error() && $Qreq->valid_post()) {
     if (!$Me->privChair) {
         Conf::msg_error("Only administrators can delete accounts.");
     } else if ($Acct->contactId == $Me->contactId) {
diff --git a/review.php b/review.php
index 7c70daa39..c6b9fc678 100644
--- a/review.php
+++ b/review.php
@@ -58,7 +58,7 @@ function review_load() {
 
 
 // cancel action
-if ($Qreq->cancel && $Qreq->post_ok()) {
+if ($Qreq->cancel) {
     $Conf->redirect_self($Qreq);
 }
 
@@ -66,7 +66,7 @@ function review_load() {
 // upload review form action
 if (isset($Qreq->uploadForm)
     && $Qreq->has_file("uploadedFile")
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     // parse form, store reviews
     $tf = ReviewValues::make_text($rf, $Qreq->file_contents("uploadedFile"),
             $Qreq->file_filename("uploadedFile"));
@@ -88,7 +88,7 @@ function review_load() {
     && $paperTable->editrrow
     && $paperTable->editrrow->reviewStatus >= ReviewInfo::RS_DELIVERED
     && $Me->can_administer($prow)
-    && $Qreq->post_ok()) {
+    && $Qreq->valid_post()) {
     $result = $Me->unsubmit_review_row($paperTable->editrrow);
     if (!Dbl::is_error($result) && $result->affected_rows) {
         $Me->log_activity_for($paperTable->editrrow->contactId, "Review {$paperTable->editrrow->reviewId} unsubmitted", $prow);
@@ -104,7 +104,7 @@ function review_load() {
 
 
 // update review action
-if (isset($Qreq->update) && $Qreq->post_ok()) {
+if (isset($Qreq->update) && $Qreq->valid_post()) {
     $tf = new ReviewValues($rf);
     $tf->paperId = $prow->paperId;
     if (($whyNot = $Me->perm_submit_review($prow, $paperTable->editrrow))) {
@@ -133,7 +133,7 @@ function review_load() {
 
 // adopt review action
 if (isset($Qreq->adoptreview)
-    && $Qreq->post_ok()
+    && $Qreq->valid_post()
     && $paperTable->editrrow
     && $Me->can_approve_review($prow, $paperTable->editrrow)) {
     $tf = new ReviewValues($rf);
@@ -162,7 +162,7 @@ function review_load() {
 
 // delete review action
 if (isset($Qreq->deletereview)
-    && $Qreq->post_ok()
+    && $Qreq->valid_post()
     && $Me->can_administer($prow)) {
     if (!$paperTable->editrrow) {
         Conf::msg_error("No review to delete.");
@@ -266,7 +266,8 @@ function download_one_text_review(ReviewInfo $rrow) {
 
 // retract review request
 if ((isset($Qreq->refuse) || isset($Qreq->decline))
-    && ($Qreq->post_ok() || $Me->capability("@ra" . $prow->paperId))) {
+    && ($Qreq->valid_post()
+        || ($Me->capability("@ra" . $prow->paperId) && !$Qreq->is_head()))) {
     $decline_email = null;
     if ($paperTable->editrrow) {
         $Qreq->email = $decline_email = $paperTable->editrrow->email;
@@ -298,7 +299,8 @@ function download_one_text_review(ReviewInfo $rrow) {
 }
 
 if (isset($Qreq->accept)
-    && ($Qreq->post_ok() || $Me->capability("@ra" . $prow->paperId))) {
+    && ($Qreq->valid_post()
+        || ($Me->capability("@ra" . $prow->paperId) && !$Qreq->is_head()))) {
     $rrow = $paperTable->editrrow;
     if (!$rrow
         || (!$Me->is_my_review($rrow) && !$Me->can_administer($prow))) {
diff --git a/reviewprefs.php b/reviewprefs.php
index 9517693a7..2e06603e4 100644
--- a/reviewprefs.php
+++ b/reviewprefs.php
@@ -44,6 +44,12 @@
 }
 
 
+// cancel action
+if ($Qreq->cancel) {
+    $Conf->redirect_self($Qreq);
+}
+
+
 // backwards compat
 if ($Qreq->fn
     && strpos($Qreq->fn, "/") === false
@@ -102,7 +108,7 @@ function savePreferences($Qreq, $reset_p) {
         Conf::msg_error(join("<br />", $aset->messages_html()));
     }
 }
-if ($Qreq->fn === "saveprefs" && $Qreq->post_ok()) {
+if ($Qreq->fn === "saveprefs" && $Qreq->valid_post()) {
     savePreferences($Qreq, true);
 }
 
@@ -114,7 +120,7 @@ function savePreferences($Qreq, $reset_p) {
 
 
 // Set multiple paper preferences
-if ($Qreq->fn === "setpref" && $Qreq->post_ok()) {
+if ($Qreq->fn === "setpref" && $Qreq->valid_post()) {
     if (!$SSel->is_empty()) {
         $new_qreq = new Qrequest($Qreq->method());
         foreach ($SSel->selection() as $p) {
@@ -197,13 +203,15 @@ function parseUploadedPreferences($text, $filename, $apply) {
         exit;
     }
 }
-if ($Qreq->fn === "saveuploadpref" && $Qreq->post_ok() && !$Qreq->cancel) {
+if ($Qreq->fn === "saveuploadpref" && $Qreq->valid_post()) {
     parseUploadedPreferences($Qreq->file, $Qreq->filename, true);
-} else if ($Qreq->fn === "uploadpref" && $Qreq->post_ok() && $Qreq->has_file("uploadedFile")) {
-    parseUploadedPreferences($Qreq->file_contents("uploadedFile"),
+} else if ($Qreq->fn === "uploadpref" && $Qreq->valid_post()) {
+    if ($Qreq->has_file("uploadedFile")) {
+        parseUploadedPreferences($Qreq->file_contents("uploadedFile"),
                              $Qreq->file_filename("uploadedFile"), false);
-} else if ($Qreq->fn === "uploadpref") {
-    Conf::msg_error("Select a preferences file to upload.");
+    } else {
+        Conf::msg_error("Select a preferences file to upload.");
+    }
 }
 
 
diff --git a/search.php b/search.php
index f067e579c..e36cbd44e 100644
--- a/search.php
+++ b/search.php
@@ -133,7 +133,7 @@ function savesearch() {
     }
 }
 
-if (($Qreq->savesearch || $Qreq->deletesearch) && $Me->isPC && $Qreq->post_ok()) {
+if (($Qreq->savesearch || $Qreq->deletesearch) && $Me->isPC && $Qreq->valid_post()) {
     savesearch();
 }
 
diff --git a/settings.php b/settings.php
index 4cdd7ed79..1fd3843f7 100644
--- a/settings.php
+++ b/settings.php
@@ -7,6 +7,10 @@
     $Me->escape();
 }
 
+if (isset($Qreq->cancel)) {
+    $Conf->redirect_self($Qreq);
+}
+
 $Sv = SettingValues::make_request($Me, $Qreq);
 $Sv->session_highlight();
 
@@ -42,7 +46,7 @@ function choose_setting_group($qreq, SettingValues $sv) {
 $Group = $Qreq->group = choose_setting_group($Qreq, $Sv);
 $_SESSION["sg"] = $Group;
 
-if (isset($Qreq->update) && $Qreq->post_ok()) {
+if (isset($Qreq->update) && $Qreq->valid_post()) {
     if ($Sv->execute()) {
         $Me->save_session("settings_highlight", $Sv->message_field_map());
         if (!empty($Sv->updated_fields())) {
@@ -54,9 +58,6 @@ function choose_setting_group($qreq, SettingValues $sv) {
         $Conf->redirect_self($Qreq);
     }
 }
-if (isset($Qreq->cancel) && $Qreq->post_ok()) {
-    $Conf->redirect_self($Qreq);
-}
 
 $Sv->crosscheck();
 
@@ -84,7 +85,7 @@ function choose_setting_group($qreq, SettingValues $sv) {
     '<main class="leftmenu-content main-column">',
     '<h2 class="leftmenu">', $Sv->group_title($Group), '</h2>';
 
-$Sv->report(isset($Qreq->update) && $Qreq->post_ok());
+$Sv->report(isset($Qreq->update) && $Qreq->valid_post());
 $Sv->render_group(strtolower($Group), ["top" => true]);
 
 
diff --git a/src/api/api_reviewtoken.php b/src/api/api_reviewtoken.php
index 30a3e22f1..62d1090b3 100644
--- a/src/api/api_reviewtoken.php
+++ b/src/api/api_reviewtoken.php
@@ -6,7 +6,7 @@ class ReviewToken_API {
     static function run(Contact $user, Qrequest $qreq) {
         assert(!$user->is_empty());
         $confirm = null;
-        if ($qreq->is_post() && $qreq->post_ok() && isset($qreq->token)) {
+        if ($qreq->valid_post() && isset($qreq->token)) {
             if (str_starts_with($qreq->token, "[")) {
                 $ttexts = json_decode($qreq->token);
             } else {
diff --git a/src/api/api_search.php b/src/api/api_search.php
index 62d3bc616..9787f0ecb 100644
--- a/src/api/api_search.php
+++ b/src/api/api_search.php
@@ -61,7 +61,7 @@ static function fieldhtml(Contact $user, Qrequest $qreq, PaperInfo $prow = null)
         foreach ($pl->message_set()->message_texts() as $m) {
             $j["errors"][] = $m;
         }
-        if ($j["ok"] && $qreq->session && $qreq->post_ok()) {
+        if ($j["ok"] && $qreq->session && $qreq->valid_token() && !$qreq->is_head()) {
             Session_API::setsession($user, $qreq->session);
         }
         return $j;
diff --git a/src/conference.php b/src/conference.php
index 328ff85df..ccd87366d 100644
--- a/src/conference.php
+++ b/src/conference.php
@@ -4761,7 +4761,7 @@ private function call_api($fn, $uf, Contact $user, Qrequest $qreq, $prow) {
         if ($method !== "GET"
             && $method !== "HEAD"
             && $method !== "OPTIONS"
-            && !$qreq->post_ok()
+            && !$qreq->valid_token()
             && (!$uf || ($uf->post ?? false))
             && (!$uf || !($uf->allow_xss ?? false))) {
             return new JsonResult(403, "Missing credentials.");
diff --git a/src/contact.php b/src/contact.php
index d53853bb7..1836bd368 100644
--- a/src/contact.php
+++ b/src/contact.php
@@ -1452,7 +1452,7 @@ function escape($qreq = null) {
             }
             $url = $this->conf->selfurl($qreq, $x, Conf::HOTURL_RAW | Conf::HOTURL_SITE_RELATIVE);
             $_SESSION["login_bounce"] = [$this->conf->dsn, $url, Navigation::page(), $_POST, Conf::$now + 120];
-            if ($qreq->post_ok()) {
+            if ($qreq->valid_token()) {
                 $this->conf->errorMsg("You must sign in to access that page. Your changes were not saved; after signing in, you may submit them again.");
             } else {
                 $this->conf->errorMsg("You must sign in to access that page.");
diff --git a/src/helpers.php b/src/helpers.php
index 3ff850ccc..b25333fa9 100644
--- a/src/helpers.php
+++ b/src/helpers.php
@@ -171,7 +171,7 @@ function json_exit($json, $arg2 = null) {
     if (JsonResultException::$capturing) {
         throw new JsonResultException($json);
     } else {
-        $json->emit($Qreq && $Qreq->post_ok());
+        $json->emit($Qreq && $Qreq->valid_token());
         exit;
     }
 }
diff --git a/src/initweb.php b/src/initweb.php
index 62b6a7193..2fad5a992 100644
--- a/src/initweb.php
+++ b/src/initweb.php
@@ -5,37 +5,6 @@
 require_once("init.php");
 global $Conf, $Me, $Qreq;
 
-// Check method: GET/HEAD/POST only, except OPTIONS is allowed for API calls
-if (!($_SERVER["REQUEST_METHOD"] === "GET"
-      || $_SERVER["REQUEST_METHOD"] === "HEAD"
-      || $_SERVER["REQUEST_METHOD"] === "POST"
-      || (Navigation::page() === "api"
-          && $_SERVER["REQUEST_METHOD"] === "OPTIONS"))) {
-    header("HTTP/1.0 405 Method Not Allowed");
-    exit;
-}
-
-// Check for PHP suffix
-if (Conf::$main->opt("phpSuffix") !== null) {
-    Navigation::get()->php_suffix = Conf::$main->opt("phpSuffix");
-}
-
-// Collect $Qreq
-$Qreq = Qrequest::make_global();
-
-// Check for redirect to https
-if (Conf::$main->opt("redirectToHttps")) {
-    Navigation::redirect_http_to_https(Conf::$main->opt("allowLocalHttp"));
-}
-
-// Mark as already expired to discourage caching, but allow the browser
-// to cache for history buttons
-header("Cache-Control: max-age=0,must-revalidate,private");
-
-// Set up Content-Security-Policy if appropriate
-Conf::$main->prepare_content_security_policy();
-
-// Initialize user if required
 function initialize_user_redirect($nav, $uindex, $nusers) {
     if ($nav->page === "api") {
         if ($nusers === 0) {
@@ -54,11 +23,45 @@ function initialize_user_redirect($nav, $uindex, $nusers) {
     }
 }
 
-function initialize_user() {
+function initialize_web() {
     global $Qreq;
     $conf = Conf::$main;
     $nav = Navigation::get();
 
+    // check PHP suffix
+    if (($php_suffix = Conf::$main->opt("phpSuffix")) !== null) {
+        $nav->php_suffix = $php_suffix;
+    }
+
+    // maybe redirect to https
+    if (Conf::$main->opt("redirectToHttps")) {
+        Navigation::redirect_http_to_https(Conf::$main->opt("allowLocalHttp"));
+    }
+
+    // collect $Qreq
+    $Qreq = Qrequest::make_global();
+
+    // check method
+    if ($Qreq->method() !== "GET"
+        && $Qreq->method() !== "POST"
+        && $Qreq->method() !== "HEAD"
+        && ($Qreq->method() !== "OPTIONS" || $nav->page !== "api")) {
+        header("HTTP/1.0 405 Method Not Allowed");
+        exit;
+    }
+
+    // mark as already expired to discourage caching, but allow the browser
+    // to cache for history buttons
+    header("Cache-Control: max-age=0,must-revalidate,private");
+
+    // set up Content-Security-Policy if appropriate
+    Conf::$main->prepare_content_security_policy();
+
+    // skip user initialization if requested
+    if (Contact::$no_guser) {
+        return;
+    }
+
     // set up session
     if (($sh = $conf->opt["sessionHandler"] ?? null)) {
         /** @phan-suppress-next-line PhanTypeExpectedObjectOrClassName, PhanNonClassMethodCall */
@@ -73,7 +76,7 @@ function initialize_user() {
         $sid = $_COOKIE[$sn];
         $l = strlen($Qreq->post);
         if ($l >= 8 && $Qreq->post === substr($sid, strlen($sid) > 16 ? 8 : 0, $l)) {
-            $Qreq->approve_post();
+            $Qreq->approve_token();
         } else if ($_SERVER["REQUEST_METHOD"] === "POST") {
             error_log("{$conf->dbname}: bad post={$Qreq->post}, cookie={$sid}, url=" . $_SERVER["REQUEST_URI"]);
         }
@@ -180,6 +183,4 @@ function initialize_user() {
     }
 }
 
-if (!Contact::$no_guser) {
-    initialize_user();
-}
+initialize_web();
diff --git a/src/listaction.php b/src/listaction.php
index fcab4b3ed..e53d54f45 100644
--- a/src/listaction.php
+++ b/src/listaction.php
@@ -32,7 +32,7 @@ static function grouped_extensions(Contact $user) {
     static private function do_call($name, Contact $user, Qrequest $qreq, $selection) {
         if ($qreq->method() !== "GET"
             && $qreq->method() !== "HEAD"
-            && !$qreq->post_ok()) {
+            && !$qreq->valid_token()) {
             return new JsonResult(403, "Missing credentials.");
         }
         $conf = $user->conf;
diff --git a/src/meetingtracker.php b/src/meetingtracker.php
index 684271910..69c204fc9 100644
--- a/src/meetingtracker.php
+++ b/src/meetingtracker.php
@@ -271,7 +271,7 @@ static function track_api(Contact $user, $qreq) {
         // or call `json_exit` on error.
 
         // track="IDENTIFIER POSITION" or track="IDENTIFIER stop" or track=stop
-        if (!$user->is_track_manager() || !$qreq->post_ok()) {
+        if (!$user->is_track_manager() || !$qreq->valid_post()) {
             return json_exit(403, "Permission error.");
         }
 
@@ -407,7 +407,7 @@ static function track_api(Contact $user, $qreq) {
     }
 
     static function trackerconfig_api(Contact $user, $qreq) {
-        if (!$user->is_track_manager() || !$qreq->post_ok()) {
+        if (!$user->is_track_manager() || !$qreq->valid_post()) {
             return json_exit(403, "Permission error.");
         }
 
diff --git a/src/partials/p_adminhome.php b/src/partials/p_adminhome.php
index 05eb0f01c..6eeeea78c 100644
--- a/src/partials/p_adminhome.php
+++ b/src/partials/p_adminhome.php
@@ -4,14 +4,15 @@
 
 class AdminHome_Partial {
     static function check_admin(Contact $user, Qrequest $qreq) {
-        assert($user->privChair && $qreq->post_ok());
-        // NB check post_ok(), but do not check method
-        if (isset($qreq->clearbug)) {
+        assert($user->privChair && $qreq->valid_token());
+        if (isset($qreq->clearbug)
+            && !$qreq->is_head()) {
             $user->conf->save_setting("bug_" . $qreq->clearbug, null);
         }
         if (isset($qreq->clearnewpcrev)
             && ctype_digit($qreq->clearnewpcrev)
-            && $user->conf->setting("pcrev_informtime", 0) <= $qreq->clearnewpcrev) {
+            && $user->conf->setting("pcrev_informtime", 0) <= $qreq->clearnewpcrev
+            && !$qreq->is_head()) {
             $user->conf->save_setting("pcrev_informtime", $qreq->clearnewpcrev);
         }
         if (isset($qreq->clearbug) || isset($qreq->clearnewpcrev)) {
diff --git a/src/partials/p_signin.php b/src/partials/p_signin.php
index e32177a2f..73bd41e63 100644
--- a/src/partials/p_signin.php
+++ b/src/partials/p_signin.php
@@ -40,7 +40,7 @@ static function signin_request(Contact $user, Qrequest $qreq, $gx) {
             Navigation::redirect();
         } else if ($user->conf->opt("httpAuthLogin")) {
             LoginHelper::check_http_auth($user, $qreq);
-        } else if ($qreq->post_ok()) {
+        } else if ($qreq->valid_post()) {
             if (!$user->is_empty() && strcasecmp($qreq->email, $user->email) === 0) {
                 Navigation::redirect();
             } else if (!$qreq->start) {
@@ -202,7 +202,7 @@ static function signout_request(Contact $user, Qrequest $qreq) {
         assert($qreq->method() === "POST");
         if ($qreq->cancel) {
             Navigation::redirect();
-        } else if ($qreq->post_ok()) {
+        } else if ($qreq->valid_post()) {
             LoginHelper::logout($user, true);
             Navigation::redirect($user->conf->hoturl("index", "signedout=1"));
         } else if (!isset($_SESSION) || $user->is_empty()) {
@@ -285,7 +285,7 @@ function create_request(Contact $user, Qrequest $qreq) {
             Navigation::redirect();
         } else if (!$user->conf->allow_user_self_register()) {
             // do nothing
-        } else if ($qreq->post_ok()) {
+        } else if ($qreq->valid_post()) {
             $info = LoginHelper::new_account_info($user->conf, $qreq);
             if ($info["ok"]) {
                 $prep = self::mail_user($user->conf, $info);
@@ -349,7 +349,7 @@ static function forgot_request(Contact $user, Qrequest $qreq) {
         assert($qreq->method() === "POST");
         if ($qreq->cancel) {
             Navigation::redirect();
-        } else if ($qreq->post_ok()) {
+        } else if ($qreq->valid_post()) {
             $info = LoginHelper::forgot_password_info($user->conf, $qreq, false);
             if ($info["ok"]) {
                 self::mail_user($user->conf, $info);
@@ -416,9 +416,9 @@ function reset_request(Contact $user, Qrequest $qreq) {
         if (preg_match('/\A\/?(U?[12][-\w]+)\/?\z/', $resetcap, $m)) {
             $this->_reset_cap = $m[1];
         } else if (strpos($resetcap, "@") !== false) {
-            if ($qreq->method() === "POST" && $qreq->post_ok()) {
+            if ($qreq->valid_post()) {
                 $nqreq = new Qrequest("POST", ["email" => $resetcap]);
-                $nqreq->approve_post();
+                $nqreq->approve_token();
                 $nqreq->set_annex("redirect", $user->conf->hoturl("resetpassword"));
                 self::forgot_request($user, $nqreq); // may redirect
                 if (Ht::problem_status_at("email")) {
@@ -439,8 +439,7 @@ function reset_request(Contact $user, Qrequest $qreq) {
 
         // check passwords
         if ($this->_reset_user
-            && $qreq->method() === "POST"
-            && $qreq->post_ok()) {
+            && $qreq->valid_post()) {
             $p1 = (string) $qreq->password;
             $p2 = (string) $qreq->password2;
             if ($p1 === "") {
diff --git a/users.php b/users.php
index 24d09b0fc..2b16e3cc9 100644
--- a/users.php
+++ b/users.php
@@ -265,7 +265,7 @@ function modify_confirm($j, $ok_message, $ok_message_optional) {
     }
 }
 
-if ($Viewer->privChair && $Qreq->modifygo && $Qreq->post_ok() && isset($papersel)) {
+if ($Viewer->privChair && $Qreq->modifygo && $Qreq->valid_post() && isset($papersel)) {
     if ($Qreq->modifytype == "disableaccount") {
         modify_confirm(UserActions::disable($Viewer, $papersel), "Accounts disabled.", true);
     } else if ($Qreq->modifytype == "enableaccount") {
@@ -343,7 +343,7 @@ function do_tags($qreq) {
     }
 }
 
-if ($Viewer->privChair && $Qreq->tagact && $Qreq->post_ok() && isset($papersel)
+if ($Viewer->privChair && $Qreq->tagact && $Qreq->valid_post() && isset($papersel)
     && preg_match('/\A[ads]\z/', (string) $Qreq->tagtype)) {
     do_tags($Qreq);
 }