Web-LangTag/search.py

#!/usr/bin/env python3

# You can test it with:
# curl --request POST  --data string=foobar\&what=language http://localhost:4000

import wsgiref.simple_server as server
import urllib.parse

# PostgreSQL interface
import psycopg2

# HTML templates http://www.yattag.org/
from yattag import Doc

PORT = 4000
#REDIRECTION_URL = "file:///home/stephane/src/Language-tags/GaBuZoMeu/registry-html" # Firefox does not accept a redirect to a file
REDIRECTION_URL = "https://www.langtag.net/registries/registry-html"

def pack(start_response, status, data, headers = []):
    datae = data.encode() # Always encode to UTF-8
    response_headers = [("Content-type", "text/plain; charset=UTF-8"), # TODO allows the type HTML
                        ("Content-Length", str(len(datae)))]
    if headers != []:
        for header in headers:
            response_headers.append(header)
    start_response(status, response_headers)
    return [datae]

def application(environ, start_response):
    if environ["REQUEST_METHOD"] != "POST":
        status = "405 Method unavailable"
        output = "Unsupported HTTP method \"%s\"\r\n" % environ["REQUEST_METHOD"]
        return pack(start_response, status, output)
    try:
        body_size = int(environ.get("CONTENT_LENGTH", 0))
    except (ValueError):
        body_size = 0
    body = environ["wsgi.input"].read(body_size)
    query = urllib.parse.parse_qsl(body.decode())
    form = {}
    headers = []
    for q in query:
        form[q[0]] = q[1]
    for mandatory in ["string", "what"]:
        if mandatory not in form:
            status = "400 Invalid request"
            output = "Missing \"%s\" in request\r\n" % mandatory
            return pack(start_response, status, output)
    if form["what"] == "language":
        sql = "SELECT * FROM Languages WHERE code = %s"
        term = form["string"].lower()
    elif form["what"] == "script":
        sql = "SELECT * FROM Scripts WHERE code = %s"
        term = form["string"].capitalize()
    else:
        status = "400 Invalid request"
        output = "Unknown search category \"%s\"\r\n" % form["what"]
        return pack(start_response, status, output)
    cursor.execute(sql, (term, ))
    mytuple = cursor.fetchone()
    status = "200 OK"
    if mytuple is not None:
        status = "308 Redirect"
        url = "%s/%s/%s.html" % (REDIRECTION_URL, form["what"], mytuple[1])
        headers.append(("Location", url))
        output = "Redirect to %s\r\n" % (url)
    else:
        if form["what"] == "language":
            sql = "SELECT * FROM Languages,Descriptions_Languages,Descriptions WHERE Descriptions_Languages.description = Descriptions.id AND Descriptions_Languages.lang = Languages.code AND position(%s in lower(Descriptions.description)) > 0;" 
        elif form["what"] == "script":
            raise "TODO not implemented"
        cursor.execute(sql, (term, ))
        found = False
        output = ""
        for tuple in cursor.fetchall():
            output += "TODO %s\r\n" % str(tuple) # TODO make it a HTML list
            found = True
        if not found:
            output = "\"%s\" not found\r\n" % term
    return pack(start_response, status, output, headers)

if __name__ == "__main__":
    conn = psycopg2.connect("dbname=lsr")
    cursor = conn.cursor()
    httpd = server.make_server("", PORT, application)
    print("Listening on port %s" % PORT)
    httpd.serve_forever()