--- /dev/null
+# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# dumps using the ".dump" command of sqlite3(1)
+package PublicInbox::WwwAltId;
+use strict;
+use PublicInbox::Qspawn;
+use PublicInbox::WwwStream;
+use PublicInbox::AltId;
+use PublicInbox::Spawn qw(which);
+our $sqlite3 = $ENV{SQLITE3};
+
+# returns prefix => pathname mapping
+# (pathname is NOT public, but prefix is used for Xapian queries)
+sub altid_map ($) {
+ my ($ibx) = @_;
+ my $altid = $ibx->{altid} or return {};
+ my %h = map {;
+ my $x = PublicInbox::AltId->new($ibx, $_);
+ "$x->{prefix}" => $x->{filename}
+ } @$altid;
+ \%h;
+}
+
+sub sqlite3_missing ($) {
+ PublicInbox::WwwResponse::oneshot($_[0], 501, \<<EOF);
+<pre>sqlite3 not available
+
+The administrator needs to install the sqlite3(1) binary
+to support gzipped sqlite3 dumps.</pre>
+</pre>
+EOF
+}
+
+sub check_output {
+ my ($r, $bref, $ctx) = @_;
+ return PublicInbox::WwwResponse::oneshot($ctx, 500) if !defined($r);
+ if ($r == 0) {
+ my $err = eval { $ctx->{env}->{'psgi.errors'} } // \*STDERR;
+ $err->print("unexpected EOF from sqlite3\n");
+ return PublicInbox::WwwResponse::oneshot($ctx, 501);
+ }
+ [200, [ qw(Content-Type application/gzip), 'Content-Disposition',
+ "inline; filename=$ctx->{altid_pfx}.sql.gz" ] ]
+}
+
+# POST $INBOX/$prefix.sql.gz
+# we use the sqlite3(1) binary here since that's where the ".dump"
+# command is implemented, not (AFAIK) in the libsqlite3 library
+# and thus not usable from DBD::SQLite.
+sub sqldump ($$) {
+ my ($ctx, $altid_pfx) = @_;
+ my $ibx = $ctx->{-inbox};
+ my $altid_map = $ibx->{-altid_map} //= altid_map($ibx);
+ my $fn = $altid_map->{$altid_pfx};
+ unless (defined $fn) {
+ return PublicInbox::WwwStream::oneshot($ctx, 404, \<<EOF);
+<pre>`$altid_pfx' is not a valid altid for this inbox</pre>
+EOF
+ }
+
+ eval { require PublicInbox::GzipFilter } or
+ return PublicInbox::WwwStream::oneshot($ctx, 501, \<<EOF);
+<pre>gzip output not available
+
+The administrator needs to install the Compress::Raw::Zlib Perl module
+to support gzipped sqlite3 dumps.</pre>
+EOF
+ $sqlite3 //= which('sqlite3');
+ if (!defined($sqlite3)) {
+ return PublicInbox::WwwStream::oneshot($ctx, 501, \<<EOF);
+<pre>sqlite3 not available
+
+The administrator needs to install the sqlite3(1) binary
+to support gzipped sqlite3 dumps.</pre>
+</pre>
+EOF
+ }
+
+ # setup stdin, POSIX requires writes <= 512 bytes to succeed so
+ # we can close the pipe right away.
+ pipe(my ($r, $w)) or die "pipe: $!";
+ syswrite($w, ".dump\n") == 6 or die "write: $!";
+ close($w) or die "close: $!";
+
+ # TODO: use -readonly if available with newer sqlite3(1)
+ my $qsp = PublicInbox::Qspawn->new([$sqlite3, $fn], undef, { 0 => $r });
+ my $env = $ctx->{env};
+ $ctx->{altid_pfx} = $altid_pfx;
+ $env->{'qspawn.filter'} = PublicInbox::GzipFilter->new;
+ $qsp->psgi_return($env, undef, \&check_output, $ctx);
+}
+
+1;