Support a direction prefix on SORT

[xapian.git] / xapian-applications / omega / omega.cc

/* omega.cc: Main module for omega (example CGI frontend for Xapian)
 *
 * Copyright 1999,2000,2001 BrightStation PLC
 * Copyright 2001 James Aylett
 * Copyright 2001,2002 Ananova Ltd
 * Copyright 2002,2003,2004,2006,2007,2008,2009,2010,2011,2014,2015,2016 Olly Betts
 *
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#include <config.h>

// If we're building against git after the expand API changed but before the
// version gets bumped to 1.3.2, we'll get a deprecation warning from
// get_eset() unless we suppress such warnings here.
#define XAPIAN_DEPRECATED(D) D

#include <cstdio>
#include <ctime>

#include <algorithm>
#include <cstring>
#include <iostream>
#include <set>

#include "safefcntl.h"
#include "safeunistd.h"

#include "omega.h"
#include "utils.h"
#include "cgiparam.h"
#include "query.h"
#include "str.h"
#include "stringutils.h"
#include "expand.h"

using namespace std;

static const char DEFAULT_STEM_LANGUAGE[] = "english";

// A character which doesn't require URL encoding, and isn't likely to appear
// in filter values.
const char filter_sep = '~';

// What we used for filter_sep in Omega < 1.3.4.
const char filter_sep_old = '-';

Xapian::Enquire * enquire;
Xapian::Database db;
Xapian::RSet rset;

map<string, string> option;

string date_start, date_end, date_span;

bool set_content_type = false;

bool suppress_http_headers = false;

string dbname;
string fmtname;
string filters, old_filters;

Xapian::docid topdoc = 0;
Xapian::docid hits_per_page = 0;
Xapian::docid min_hits = 0;

// percentage cut-off
int threshold = 0;

Xapian::valueno sort_key = Xapian::BAD_VALUENO; // Don't sort.
bool reverse_sort = true;
bool sort_after = false;
Xapian::Enquire::docid_order docid_order = Xapian::Enquire::ASCENDING;

Xapian::valueno collapse_key = 0;
bool collapse = false;

static string
map_dbname_to_dir(const string &database_name)
{
    return database_dir + database_name;
}

int main(int argc, char *argv[])
try {
    read_config_file();

    MCI val;
    pair<MCI, MCI> g;

    option["flag_default"] = "true";

    // set default thousands and decimal separators: e.g. "16,729 hits" "1.4K"
    option["decimal"] = ".";
    option["thousand"] = ",";
    
    // set the default stemming language
    option["stemmer"] = DEFAULT_STEM_LANGUAGE;

    // FIXME: set cout to linebuffered not stdout.  Or just flush regularly...
    //setvbuf(stdout, NULL, _IOLBF, 0);

    const char * method = getenv("REQUEST_METHOD");
    if (method == NULL) {
        if (argc > 1 && (argv[1][0] != '-' || strchr(argv[1], '='))) {
            // omega 'P=information retrieval' DB=papers
            // check for a leading '-' on the first arg so "omega --version",
            // "omega --help", and similar take the next branch
            decode_argv(argv + 1);
        } else {
            // Seems we're running from the command line so give version
            // and allow a query to be entered for testing
            cout << PROGRAM_NAME " - " PACKAGE " " VERSION "\n";
            if (argc > 1) exit(0);
            cout << "Enter NAME=VALUE lines, end with blank line\n";
            decode_test();
        }
    } else {
        if (*method == 'P')
            decode_post();
        else
            decode_get();
    }

    try {
        // get database(s) to search
        dbname.resize(0);
        set<string> seen; // only add a repeated db once
        g = cgi_params.equal_range("DB");
        for (MCI i = g.first; i != g.second; ++i) {
            const string & v = i->second;
            if (!v.empty()) {
                size_t p = 0, q;
                while (true) {      
                    q = v.find('/', p);
                    string s(v, p, q - p);
                    if (!s.empty() && seen.find(s) == seen.end()) {
                        // Translate DB parameter to path of database directory
                        if (!dbname.empty()) dbname += '/';
                        dbname += s;
                        db.add_database(Xapian::Database(map_dbname_to_dir(s)));
                        seen.insert(s);
                    }
                    if (q == string::npos) break;
                    p = q + 1;
                }
            }
        }
        if (dbname.empty()) {
            dbname = default_db;
            db.add_database(Xapian::Database(map_dbname_to_dir(dbname)));
        }
        enquire = new Xapian::Enquire(db);
    }
    catch (const Xapian::Error &) {
        enquire = NULL;
    }

    hits_per_page = 0;
    val = cgi_params.find("HITSPERPAGE");
    if (val != cgi_params.end()) hits_per_page = atol(val->second.c_str());
    if (hits_per_page == 0) {
        hits_per_page = 10;
    } else if (hits_per_page > 1000) {
        hits_per_page = 1000;
    }

    val = cgi_params.find("DEFAULTOP");
    if (val != cgi_params.end()) {
        const string & v = val->second;
        if (v == "OR" || v == "or")
            default_op = Xapian::Query::OP_OR;
    }

    val = cgi_params.find("FMT");
    if (val != cgi_params.end()) {
        const string & v = val->second;
        if (!v.empty()) fmtname = v;
    }
    if (fmtname.empty())
        fmtname = default_template;

    val = cgi_params.find("MORELIKE");
    if (enquire && val != cgi_params.end()) {
        const string & v = val->second;
        Xapian::docid docid = atol(v.c_str());
        if (docid == 0) {
            // Assume it's MORELIKE=Quid1138 and that Quid1138 is a UID
            // from an external source - we just find the correspond docid
            Xapian::PostingIterator p = db.postlist_begin(v);
            if (p != db.postlist_end(v)) docid = *p;
        }

        if (docid != 0) {
            Xapian::RSet tmprset;
            tmprset.add_document(docid);

            OmegaExpandDecider decider(db);
            set_expansion_scheme(*enquire, option);
#if XAPIAN_AT_LEAST(1,3,2)
            Xapian::ESet eset(enquire->get_eset(40, tmprset, &decider));
#else
            Xapian::ESet eset(enquire->get_eset(40, tmprset, 0,
                                                expand_param_k, &decider));
#endif
            string morelike_query;
            for (Xapian::ESetIterator i = eset.begin(); i != eset.end(); i++) {
                if (!morelike_query.empty()) morelike_query += ' ';
                morelike_query += pretty_term(*i);
            }
            set_probabilistic_query(string(), morelike_query);
        }
    } else {
        // add expand/topterms terms if appropriate
        string expand_terms;
        if (cgi_params.find("ADD") != cgi_params.end()) {
            g = cgi_params.equal_range("X");
            for (MCI i = g.first; i != g.second; i++) {
                const string & v = i->second;
                if (!v.empty()) {
                    if (!expand_terms.empty())
                        expand_terms += ' ';
                    expand_terms += v;
                }
            }
        }

        // collect the unprefixed prob fields
        g = cgi_params.equal_range("P");
        for (MCI i = g.first; i != g.second; i++) {
            const string & v = i->second;
            if (!v.empty()) {
                // If there are expand terms, append them to the first
                // non-empty P parameter.
                if (!expand_terms.empty()) {
                    string q = v;
                    q += ' ';
                    q += expand_terms;
                    set_probabilistic_query(string(), q);
                    expand_terms = string();
                } else {
                    set_probabilistic_query(string(), v);
                }
            }
        }

        if (!expand_terms.empty()) {
            set_probabilistic_query(string(), expand_terms);
        }
    }

    g.first = cgi_params.lower_bound("P.");
    g.second = cgi_params.lower_bound("P/"); // '/' is '.' + 1.
    for (MCI i = g.first; i != g.second; i++) {
        const string & v = i->second;
        if (!v.empty()) {
            string pfx(i->first, 2, string::npos);
            set_probabilistic_query(pfx, v);
        }
    }

    // set any boolean filters
    g = cgi_params.equal_range("B");
    if (g.first != g.second) {
        vector<string> filter_v;
        for (MCI i = g.first; i != g.second; i++) {
            const string & v = i->second;
            // we'll definitely get empty B fields from "-ALL-" options
            if (!v.empty() && C_isalnum(v[0])) {
                add_bterm(v);
                filter_v.push_back(v);
            }
        }
        sort(filter_v.begin(), filter_v.end());
        vector<string>::const_iterator j;
        for (j = filter_v.begin(); j != filter_v.end(); ++j) {
            const string & bterm = *j;
            string::size_type e = bterm.find(filter_sep);
            if (usual(e == string::npos)) {
                filters += bterm;
            } else {
                // If a filter contains filter_sep then double it to escape.
                // Each filter must start with an alnum (checked above) and
                // the value after the last filter is the default op, which
                // is encoded as a non-alnum so filter_sep followed by
                // something other than filter_sep must be separating filters.
                string::size_type b = 0;
                while (e != string::npos) {
                    filters.append(bterm, b, e + 1 - b);
                    b = e;
                    e = bterm.find(filter_sep, b + 1);
                }
                filters.append(bterm, b, string::npos);
            }
            filters += filter_sep;
            old_filters += bterm;
            old_filters += filter_sep_old;
        }
    }

    // set any negated boolean filters
    g = cgi_params.equal_range("N");
    if (g.first != g.second) {
        vector<string> filter_v;
        for (MCI i = g.first; i != g.second; i++) {
            const string & v = i->second;
            // we'll definitely get empty N fields from "-ALL-" options
            if (!v.empty() && C_isalnum(v[0])) {
                add_nterm(v);
                filter_v.push_back(v);
            }
        }
        sort(filter_v.begin(), filter_v.end());
        vector<string>::const_iterator j;
        for (j = filter_v.begin(); j != filter_v.end(); ++j) {
            const string & nterm = *j;
            string::size_type e = nterm.find(filter_sep);
            filters += '!';
            if (usual(e == string::npos)) {
                filters += nterm;
            } else {
                // If a filter contains filter_sep then double it to escape.
                // Each filter must start with an alnum (checked above) and
                // the value after the last filter is the default op, which
                // is encoded as a non-alnum so filter_sep followed by
                // something other than filter_sep must be separating filters.
                string::size_type b = 0;
                while (e != string::npos) {
                    filters.append(nterm, b, e + 1 - b);
                    b = e;
                    e = nterm.find(filter_sep, b + 1);
                }
                filters.append(nterm, b, string::npos);
            }
            filters += filter_sep;
            // old_filters predates 'N' terms, so if there are 'N' terms this
            // is definitely a different query.
            old_filters.clear();
        }
    }

    // date range filters
    val = cgi_params.find("START");
    if (val != cgi_params.end()) date_start = val->second;
    val = cgi_params.find("END");
    if (val != cgi_params.end()) date_end = val->second;
    val = cgi_params.find("SPAN");
    if (val != cgi_params.end()) date_span = val->second;

    // If more default_op values are supported, encode them as non-alnums
    // other than filter_sep or '!'.
    filters += (default_op == Xapian::Query::OP_AND ? '.' : '-');
    filters += date_start;
    filters += filter_sep;
    filters += date_end;
    filters += filter_sep;
    filters += date_span;

    if (!old_filters.empty()) {
        old_filters += date_start;
        old_filters += filter_sep_old;
        old_filters += date_end;
        old_filters += filter_sep_old;
        old_filters += date_span;
        old_filters += (default_op == Xapian::Query::OP_AND ? 'A' : 'O');
    }

    // Percentage relevance cut-off
    val = cgi_params.find("THRESHOLD");
    if (val != cgi_params.end()) {
        threshold = atoi(val->second.c_str());
        if (threshold < 0) threshold = 0;
        if (threshold > 100) threshold = 100;
    }

    // collapsing
    val = cgi_params.find("COLLAPSE");
    if (val != cgi_params.end()) {
        const string & v = val->second;
        if (!v.empty()) {
            collapse_key = atoi(v.c_str());
            collapse = true;
            filters += filter_sep;
            filters += str(collapse_key);
            if (!old_filters.empty()) {
                old_filters += filter_sep_old;
                old_filters += str(collapse_key);
            }
        }
    }

    // docid order
    val = cgi_params.find("DOCIDORDER");
    if (val != cgi_params.end()) {
        const string & v = val->second;
        if (!v.empty()) {
            char ch = v[0];
            if (ch == 'D') {
                docid_order = Xapian::Enquire::DESCENDING;
                filters += 'D';
                if (!old_filters.empty()) old_filters += 'D';
            } else if (ch != 'A') {
                docid_order = Xapian::Enquire::DONT_CARE;
            } else {
                filters += 'X';
                if (!old_filters.empty()) old_filters += 'X';
            }
        }
    }

    // sorting
    val = cgi_params.find("SORT");
    if (val != cgi_params.end()) {
        const char * p = val->second.c_str();
        if (*p == '-' || *p == '+') {
            reverse_sort = (*p == '-');
            ++p;
        }
        sort_key = atoi(p);

        val = cgi_params.find("SORTREVERSE");
        if (val != cgi_params.end() && atoi(val->second.c_str()) != 0) {
            reverse_sort = !reverse_sort;
        }

        val = cgi_params.find("SORTAFTER");
        if (val != cgi_params.end()) {
            sort_after = (atoi(val->second.c_str()) != 0);
        }

        // Add the sorting related options to filters too.
        //
        // Note: old_filters really does encode a reversed sort as 'F' and a
        // non-reversed sort as 'R' or 'r'.
        //
        // filters has them the other way around for sanity (except in
        // development snapshot 1.3.4, which was when the new filter encoding
        // was introduced).
        filters += str(sort_key);
        if (!old_filters.empty()) old_filters += str(sort_key);
        if (sort_after) {
            if (reverse_sort) {
                filters += 'R';
                if (!old_filters.empty()) old_filters += 'F';
            } else {
                filters += 'F';
                if (!old_filters.empty()) old_filters += 'R';
            }
        } else {
            if (!reverse_sort) {
                filters += 'f';
                if (!old_filters.empty()) old_filters += 'r';
            }
        }
    }

    if (old_filters.empty()) old_filters = filters;

    // min_hits (fill mset past topdoc+(hits_per_page+1) to
    // topdoc+max(hits_per_page+1,min_hits)
    val = cgi_params.find("MINHITS");
    if (val != cgi_params.end()) {
        min_hits = atol(val->second.c_str());
    }

    parse_omegascript(); 
} catch (const Xapian::Error &e) {
    if (!set_content_type && !suppress_http_headers)
        cout << "Content-Type: text/html\n\n";
    cout << "Exception: " << html_escape(e.get_msg()) << endl;
} catch (const std::exception &e) {
    if (!set_content_type && !suppress_http_headers)
        cout << "Content-Type: text/html\n\n";
    cout << "Exception: std::exception " << html_escape(e.what()) << endl;
} catch (const string &s) {
    if (!set_content_type && !suppress_http_headers)
        cout << "Content-Type: text/html\n\n";
    cout << "Exception: " << html_escape(s) << endl;
} catch (const char *s) {
    if (!set_content_type && !suppress_http_headers)
        cout << "Content-Type: text/html\n\n";
    cout << "Exception: " << html_escape(s) << endl;
} catch (...) {
    if (!set_content_type && !suppress_http_headers)
        cout << "Content-Type: text/html\n\n";
    cout << "Caught unknown exception" << endl;
}