Python Notes: Picture-of-the-Day

  1. The information presented here is intended for educational use.
  2. The information presented here is provided free of charge, as-is, with no warranty of any kind.
  3. Edit: 2024-07-14

Overview

file-1: HTML test page

<!DOCTYPE html>
<html lang="en">
<head>
    <meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta content="#ffffff" name="theme-color">
    <title>Test Pix</title>
    <link href="css/nsr-20170909.css" rel="stylesheet" type="text/css">
    <script src="js/picture-viewer72.js"></script>
</head>
<body lang="en-ca" >
    <h4>Test-Pix</h4>
    <table class="tbl-blue" style="width:100%">
	<tr><td>msg</td> <td id="msg"></td></tr>
	<tr><td>src</td> <td id="src"></td></tr>
	<tr><td style="width:50px">com</td>
            <td id="comment" style="min-width:90%"></td>
	</tr>
	<tr><td>txt</td>
	    <td id="text" style="text-align: center; font-weight: bold;height:280px"></td>
	</tr>
	<tr><td>calc</td><td id="calc"></td></tr>
	<tr><td>mmdd</td><td id="mmdd"></td></tr>
	</table>
<script>
    testYear();
</script>
</body>
</html>

file-2: HTML production page

<!DOCTYPE html>
<html lang="en-ca">
<head>
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Hackerspace - STEMspace</title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/css/bootstrap.min.css" rel="stylesheet">
    <script src="https://cdn.jsdelivr.net/npm/jquery@3.7.1/dist/jquery.slim.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/js/bootstrap.bundle.min.js"></script>
    <link href="css/nsr-20170909.css" rel="stylesheet" type="text/css">
    <script src="js/picture-viewer74.js"></script>
</head>
<body>

  ...snip...

<div class="col-xs-12 col-sm-5 col-md-4 col-lg-3" id="pixoftheday"
    style="text-align: center; font-weight: bold;height:280px">
    <img alt="400ky of atmospheric CO2" src="images/carbon_dioxide_400kyr.png" style="height:80%">
    <div style="text-align:center;margin-top:5px;font-weight:bold">
	CO2 levels cycle between<br>180 and 280 ppm every 120K years</div>
    </div>
</div>

  ...snip...

<script>
//
//	use a namespace technique for declaring functions
//	p.s. my implementation is way too complicated for most sites
//
//    create an object called nsNSR1
//
var nsNSR1 = function(){
    //
    //    show/hide the xmas alert
    //
    function xmas_support(){
        var snap = new Date();
        var ccyy = snap.getFullYear();
        var mm = snap.getMonth();
        //var dow    = snap.getDay();
        var dd = snap.getDate();
        if (mm == 0){
            ccyy--;
        }
        // display for Western Christmas
        document.getElementById("xmasyear").outerHTML = (ccyy);
        if ((mm == 11) || ((mm == 0) && (dd <= 2))){
            document.getElementById("xmasmsg").hidden = false;
        }else{
            document.getElementById("xmasmsg").hidden = true;
        }
    }
    //
    //    enable a hyperlink (old site only)
    //
    function moving(){
        var this_host = window.location.hostname;
        var caveat = this_host.indexOf('neilrieck.net');
        console.log('moving-caveat:' + this_host);
        console.log('moving-caveat:' + caveat);
        if (caveat<0){
            // enable HTML warning on the page
            document.getElementById("moving9").hidden = false;
        }
    }
    //
    //    pod (picture-of-day) notes:
    //    1) Rotate between 4 images (3 environmental and 1 scientist)
    //    2) this routine calls things in namespace "nsNSR7" defined in picture-viewer75.js
    //    3) image "co2-400kyr" is already on the screen in case of failures here
    //    4) steps:
    //        1:        load "local co2-400kyr" (into slot 0)
    //                load "NOAA  co2-data"   (into slot 1)
    //                load "NOAA  co2-trend"  (into slot 2)
    //                load "local Scientist"  (into slot 3)
    //        2-5:    kill 3 seconds
    //        6:        test if NOAA images loaded
    //                load "local co2-data"   (into slot 1 only if it is empty)
    //                load "local co2-trend"  (into slot 2 only if it is empty)
    //        7-10:    kill 3 seconds          (only if necessary)
    //        11:        stop timer9 then check if we have four images;
    //                 if all is well then start timer8 to rotate between four prefetched images
    //
    function pod(){                                    // pod = picture-of-day
        var pix9 = 0;                                // init
        console.log("starting pod()");
        function init(){
            console.log("pod-init()");
            try{
                console.log("init1: ", JSON.stringify( Object.assign ( {}, nsNSR7.myTxt )));
                nsNSR7.initArrays(10);
                console.log("init2: ", JSON.stringify( Object.assign ( {}, nsNSR7.myTxt )));
                for (i=1;i<10;i++){
                    console.log("hack"+i, JSON.stringify( Object.assign ( {}, nsNSR7.myTxt[i] )));
                }
            }catch(e){
                console.log("init-error:",e);
            }        
        }
        // init();
        // start timer-9
        var intervalId9 = setInterval(
            function(){
                pix9++;
                console.log("pod-pix9: "+pix9);
                if (pix9==1){
                    nsNSR7.fetchDefault(0,8000);    // co2 400kyr (local)
                    nsNSR7.fetchDefault(1,8002);    // co2-data (NOAS)
                    nsNSR7.fetchDefault(2,8004);    // co2-trend (NOAS)
                    nsNSR7.fetchToday(3);            // scientist picture-of-the-day
                    return;
                }
                if (pix9<6){
                    // kill some time
                    return;
                }
                if (pix9==6){
                    // test if NOAA images loaded
                    // image1: if no 8002 then load 8001
                    var work = 0;
                    var tmp;
                    try{
                        tmp=nsNSR7.imageArray[1].width;
                    }catch(e){
                        console.log("-e-image1: ",e);
                        tmp=0;
                    }
                    if (tmp==0){
                        console.log("pod: 8002 fubar so loading 8001");
                        nsNSR7.fetchDefault(1,8001);    // co2-data (local)
                        work += 1;                        // did some work
                    }
                    // image2: if no 8004 then load 8003
                    var tmp;
                    try{
                        tmp=nsNSR7.imageArray[2].width;
                    }catch(e){
                        console.log("-e-image2: ",e);
                        tmp=0;
                    }
                    if (tmp==0){
                        console.log("pod: 8004 fubar so loading 8003");
                        nsNSR7.fetchDefault(2,8003);    // co2-trend-local
                        work += 1;                      // did some work
                    }
                    if (work==0){                       // if no need to wait
                        pix9=11;
                        console.log("pod-pix9 jumps to: "+pix9);
                    }else{
                        return;
                    }
                }
                if (pix9<11){                            // killing time
                    return;
                }
                if (pix9==11){
                    console.log("pod: stopping timer #9");
                    clearInterval(intervalId9);            // stop this timer
                    var recipe = 0;                        // init
                    try{
                        // make sure we have four good images
                        for (var i=0;i<4;i++){
                            console.log("image: "+i+" size:",nsNSR7.imageArray[i].width);
                            if (nsNSR7.imageArray[i].width==0){
                                console.log("oops: image "+i+" is zero length");
                                return;
                            }else{
                                recipe++;
                            }
                        }
                    }catch(e){
                        console.log("recipe error: ",e);
                        recipe = 99;
                    }
                    console.log("recipe: "+recipe);
                    if (recipe != 4){
                        console.log("pod: recipe error so will not rotate any images");
                    }else{
                        console.log("pod: arming timer #8");
                        var pix8=0;                        // init
                        var intervalId8 = setInterval(
                            function (){
                                pix8++;                    //
                                pix = pix8%4;            // only 4 pictures: 0-3
                                console.log("pod-pix8: " +pix8+" index: "+pix);
                                if (pix8 >= 24){
                                    console.log("pod: stopping timer #8");
                                    clearInterval(intervalId8);
                                }else{
                                    console.log("pod-inject:" + nsNSR7.myTxt[pix]);
                                    document.getElementById("pixoftheday").innerHTML = nsNSR7.myTxt[pix];
                                }
                            }, 6000);                    // 6 seconds 
                    }
                }
            }, 1000);                                    // 1 second
    }
    //
    //    expose anything we want externally referenced
    //
    return{
        xmas_support:xmas_support,
        moving:moving,
        pod:pod
    }
}();
//    now execute these tasks
console.log("-i-local javascript tasks begin");
function show_answer(element) {
 element.parentNode.children[2].style.visibility = "visible";
}
function hide_answer(element) {
 element.parentNode.children[2].style.visibility = "hidden";
}
// nsNSR1.xmas_support();
// nsNSR1.moving();
// odyssey_viewer();
console.log("-i-queueing a 2-second delay");
setTimeout(function() {
    console.log("-i-timer expired");
    nsNSR1.pod();
}, 2000);
// ##############################
nsNSR1.pod();	// execute my function
</script>
</body>
</html>

file-3: JavaScript

// =======================================================================
// title : picture-viewer75.js
// author: Neil Rieck (Waterloo, Ontario, Canada)
// notes :
// 1) In order to avoid name clashes with other javascript routines, this
//    code block declares functions and variables inside a namespace. So 
//    any labels you wish published must be added to the return statment
//    at the end of this file
// 2) this file currently supports default date codes: 8000-8004
//
// ver when       what 
// --- ---------- --------------------------------------------------------
//   4 2019-11-28 modified to work with my Python-based cgi
//   5 2020-04-04 code cleanup
//   6 2020-10-29 moved everything into a namespace
//  71 2021-10-30 better overlapping AJAX (pulling from slow sites)
//  72 2021-10-31 XmlDoc is no longer global (what was I thinking?)
//  73 2021-12-01 removed protocol from url
//  74 2022-08-20 changes to allow 3-5 default pictures
//  75 2024-07-06 experiments with async fetches. See: myAsync[]
// =======================================================================
//
//	start of name-space
//
var nsNSR7 = (function() {
//
'use strict';		// no kid-stuff here
//
//	some private variables
//
var debug=0;		//
var slot=0;		//
var mySrc=[];		// image source
var myTxt=[];		// image text (from payload)
var imageArray=[];	// image data
var myAsync=[];		// array of objects
//
//	store data as well as preload the image
//
function preloadImage(url,txt,slot){
    if (typeof slot == "undefined"){
	var slot=9;
    }
    console.log("preload url: "+url+" slot: "+slot);
    try{
	mySrc[slot] = url;
	myTxt[slot] = txt;
	imageArray[slot] = new Image();
	imageArray[slot].src = url;
    }catch(e){ 
	console.error("preload url: "+url+" slot: "+slot+" error: ",e);
    }
}
//
//	start_ajax (start an AJAX transaction)
//	Note: use new to create copies of this object
//
function start_ajax(msg,slot){
    console.log("start ajax slot: "+slot);
    // still some Microsoft browsers out there 
    if (typeof XMLHttpRequest == "undefined")
	XMLHttpRequest=function(){
	    try { return new ActiveXObject("Msxml2.XMLHTTP.6.0")    } catch (e) {}
	    try { return new ActiveXObject("Msxml2.XMLHTTP.3.0")    } catch (e) {}
	    try { return new ActiveXObject("Msxml2.XMLHTTP")        } catch (e) {}
	    try { return new ActiveXObject("Microsoft.XMLHTTP")     } catch (e) {}
	    throw new Error("This browser does not support XMLHttpRequest.")
        }
    if (msg != ""){
	var xhr=new XMLHttpRequest();
	if (xhr != null){
	    xhr.open("GET", msg, true);			// async=true
	    xhr.timeout=3000;				// 3 seconds max
	    xhr.ontimeout = function(){
		console.log("Timeout:",slot);
	    }
	    xhr.onreadystatechange=function(){
		if (xhr.readyState == 4 && xhr.status == 200){
		    var resp$=xhr.responseText;
			ajax_xml_extract(resp$);
		}
	    }
	    console.log("sending ajax request for slot: "+slot)
	    xhr.send(null);				// not null for POST
	}
    }
}
//
//	ajax_xml_extract
//
function ajax_xml_extract(resp$){
	// console.log("ajax-xml-extract raw:",resp$);
    try{
	if (window.DOMParser) {
		var parser=new DOMParser();
		var xml=parser.parseFromString(resp$,"text/xml");
	}else{
		var xml=new ActiveXObject("Microsoft.XMLDOM");
		xml.async=false;
		xml.loadXML(resp$);
	}
	var src	= get_xml_data("src",xml);
	var txt = get_xml_data("text",xml);
	var slot= get_xml_data("slot",xml);
	console.log("calling preloadImage for slot: "+slot)
	preloadImage(src,txt,slot);
    }catch(e){
	console.error("ajax_xml_extract:",e)
}
}
//
//	does string 'x' represent a positive integer?
//
function isStrInt(x){
    x=x.replace(/\s/g,'');
    if (x=="") return false;
    try{
	y = parseInt(x);
    }catch(e){
	y = -1;
    }
    if(y>0){
    	return true;
    }else{
	return false;
    }
}
function htmlEncode(str) {
    return String(str).replace(/&/g, '&').replace(//g, '>').replace(/"/g, '"');
}
function htmlDecode(str) {
    return String(str).replace(/</g, '<').replace(/>>/g, '>').replace(/"/g, '"').replace(/&/g, '&');
}
//
//	get_xml_data (look for one item)
//
function get_xml_data(tag,xml){
    var x;
    try{
	x = xml.getElementsByTagName(tag)[0].childNodes[0].nodeValue;
    }catch(e){
	console.error("get-xml-data: ",e);
	x = null;
    }
    return(x);
}
//
//	get number of days per month
//
function monthSize(x){
  switch(x) {
  case 2:
    return(28);
  case 9:
  case 4:
  case 6:
  case 11:
  	return(30);
  default:
    return(31);
  }
}
function pad(num, size) {
  var s = num+"";
  while (s.length < size) s = "0" + s;
  return s;
}
//
//	test picture-of-the-day logic for the whole year
//	caveat: only used in testing
//
function testYear(){
    debug=1;		// change global
    var mm=0;		// month
    var dd=0;		// day
    var mmdd="";
    var intervalId = setInterval(function(){
	if (mm==0){
	    mm=1;
	    dd=1;
	}else{
	    dd++;
	    limit=monthSize(mm);
	    if (dd>limit){
		mm++;
		dd=1;
	    }
	}
	if (mm>12){
	    clearInterval(intervalId);
	}else{
	    mmdd=junk=pad(mm,2)+pad(dd,2);
	    console.log("mmdd:"+mmdd);
	    document.getElementById("mmdd").innerHTML="mmdd: "+mmdd;
	    msg = "https://neilrieck.net/cgi-bin/daily_pix?xml=1&slot=0&mmdd="+mmdd;
	    start_ajax(msg,0);
	}
    }, 1000);
}
//
//	get one picture for today
//
function fetchToday(slot){
	var d	= new Date();
	var mm	= d.getMonth();	// 0..11
	var dd  = d.getDate();	// 1..31
	var mmdd= pad(mm+1,2)+pad(dd,2);
	console.log("fetchToday-mmdd: "+mmdd);
	var msg = "https://neilrieck.net/cgi-bin/daily_pix?xml=1&slot="+slot+"&mmdd="+mmdd;
	// start_ajax(msg,slot);
	myAsync.push(new start_ajax(msg,slot));		// create one-time use object
}
//
//	get default picture
//	8000: co2_400kyr
//	8001: co2_levels (static-local)
//	8002: co2_levels (dynamic-remote)
//
function fetchDefault(slot,mmdd){
	if (typeof mmdd == "undefined"){
		var slot=8000;
	}
	if ((mmdd<8000)||(mmdd>8002)){
		slot=8000;
	}
	console.log("fetchDefault-mmdd: "+mmdd+" slot: "+slot);
	var msg = "https://neilrieck.net/cgi-bin/daily_pix?xml=1&slot="+slot+"&mmdd="+mmdd;
	// start_ajax(msg,slot);
	myAsync.push(new start_ajax(msg,slot));		// create one-time use object
}
//
//	end-of-name-space logic
//	now publish the names of anything referenced externally
//
return{
	preloadImage:preloadImage,
	fetchToday:fetchToday,
	fetchDefault:fetchDefault,
	mySrc:mySrc,
	myTxt:myTxt,
	imageArray:imageArray
}
// end of name-space
}());
// end of file

file-4: Python3 (optional launcher)

note: this file is usually located in the cgi-bin folder of your web server
#!/usr/bin/python3
# title : daily_pix
# author: Neil Rieck (Waterloo, Ontario, Canada)
# edit  : 2022-09-30
# notes : forces Python3 to do a one-time compile of whatever is imported so
#         'file_100.py' is compiled to '__pycache__/file_100.cpython-36.pyc'
import daily_pix_133
daily_pix_133.main()

file-5: Python3 (program)

note: in this example, this file is found under cgi-bin (but you could move it anywhere else provided Apache can access it)
#!/usr/bin/python3
'''
===================================================================================
title  : daily_pix_133.py
author : Neil Rieck
history:
ver when       what
100 2019-11-23 calls daily_pix_mysql.py
101 2019-12-15 cleanup
102 2020-04-18 added JSON support
130 2020-05-09 moved db into here; changed the connector; cursor now returns a dict
    2020-07-11 tiny fix in anniversary/season calc (see: 'calc' vs 'calc1')
131 2020-07-11 replaced format strings with f strings
    2021-12-01 removed 'http:' from urls (to properly support CORS)
132 2022-08-22 now also encode 'comment' in output_xml
133 2022-09-30 added support for pattern: +ccyy+
purpose:
1) for a given month-day (format: mmdd) return a picture along with associated text
2) optionally, return the data in XML or JSON format
3) these PEP8 rules are disabled: E305,E501 so I can code in a traditional way
4) I used vim8 along with the pymode plugin
===================================================================================
'''
import cgi
import datetime
import json
import sys
import html
import mysql.connector as db
#
#   constants
#
HOST = "neilrieck.net"
#
#   common function to BAIL (will be visible in the browser's console)
#
def errorExit(msg):
    print("content-type: text/plain; charset=utf-8")
    print("")
    print(msg)
    sys.exit()
#
#   logIt (a simple file-based logger)
#   caveat: if SELinux is enabled then write to /var/log/daily_pix_msg_log.txt
#
def logIt(msg):
    try:
        fn = "daily_pix_msg_log.txt"
        f = open(fn, "a")
        f.write(f"msg: {msg}\r\n")
        f.close()
    except Exception:
        pass
#
#   do that database thing
#
def get_record(parm):
    try:
        con = db.connect(host='127.0.0.1', user='read123', passwd='read123', database='hack1')
        cur = con.cursor(dictionary=True)                           # force return of dict
        cmd = ("select * from pixofday "
               f"where (mmdd1 <= {parm}) and (mmdd2 >= {parm}) "
               "order by concat(mmdd2,mmdd1) limit 1")
        cur.execute(cmd)
        # row = cur.fetchall()                                      # returns a list of tuples (or dicts)
        row = cur.fetchone()                                        # returns a tuple (or dict)
        return row
    except Exception as e:
        msg = f"Exception: {e} while opening database"
        logIt(msg)
        errorExit(msg)
'''
===============================================================

 <<< general description >>>

 1) database field definitions
   0: mmdd1   - start date
   1: mmdd2   - end date
   2: comment -
   3: calc    - used to do an anniversary (or season) calculation
   4: src     - image source
   5: text1   - usually a title associated with the photo
   6: text2
   7: text3
 2) data:
   1: each record will indicate that a certain photo be shown between mmmdd1 and mmdd2
   2: one special record has mmdd1="0000" and mmdd2="9999" so something will always be returned
 3) logic:
   1: the 'src' field contains an image location like these two examples:
      1) local:  /images/Edmond_Halley.jpg
      2) remote: https://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo.png
   2: any entry not containing "http" will need a local prefix
   3: text1 to text3 contain HTML so merge them into one string then test for the following patterns:
   4: if we detect the string "+xxx+" then replace it with the resultant 'src' string seen at the end of step 2
   5: if we detect the string "+host+" then replace it with the default HOST of this site
   6: if we detect the string "+calc+" then do an season calculation (eg. 45th season of Quirks+Quarks)
   7: if we detect the string "+calc1+" then do an offset+1 calculation (eg. 50th Anniversary of Oktoberfest)
   8: if we detect the string "+ccyy+" then we will replace it with the current year
   9: return data to caller via XML or JSON (this means the data must be properly escaped)
 4) Cross-Origin Resource Sharing (CORS)
    For AJAX use you must add a few Cross-Origin Resource Sharing (CORS) directives to Apache config like so:
    <Directory "/var/www/html/cgi-bin">
      AllowOverride None
      Options None
      Require all granted
      # 1) CORS for initial AJAX testing.
      #Header set Access-Control-Allow-Origin "*"
      # 2) CORS for single second site support (this Apache instance runs on "https://neilrieck.net"
      # but we want to allow AJAX access from "http://www3.sympatico.ca/n.rieck/")
      Header set Access-Control-Allow-Origin http://www3.sympatico.ca
      Header set Access-Control-Allow-Headers "Content-Type,Accept"
      Header merge Vary Origin
      Header set MyHeader "Neil's Hack"
     </Directory>
===============================================================
'''
#
#   raw data in :: cooked data out
#
def process_data(row):
    imgSrc = row['src']                                             # LOGIC-1
    if (imgSrc.find('http') == -1):                                 # LOGIC-2 (local or remote)
        imgSrc = ".." + imgSrc                                      # would '/images' be better?
    allText = row['text1'] + row['text2'] + row['text3']            # LOGIC-3
    temp = allText.find('+xxx+')                                    # LOGIC-4
    if (temp != -1):                                                # if +xxx+ was found...
        allText = allText[:temp] + imgSrc + allText[temp+5:]        #
    temp = allText.find('+host+')                                   # LOGIC-5
    if (temp != -1):                                                # if +host+ was found...
        allText = allText[:temp] + HOST + allText[temp+6:]          #
    temp = allText.find('+calc+')                                   # LOGIC-6 (season number)
    if (temp != -1):                                                # if +calc+ was found...
        year = datetime.datetime.now().strftime('%Y')               #
        try:                                                        #
            season = int(row['calc'])                               # eg. ccyy
        except Exception as e:                                      #
            season = 1900                                           #
            msg = f"error: {e}"                                     #
            logIt(msg)                                              #
        diff = int(year) - season                                   #
        allText = allText[:temp] + str(diff) + allText[temp+6:]     #
    temp = allText.find('+calc1+')                                  # LOGIC-7 (anniversary)
    if (temp != -1):                                                # if +calc1+ was found...
        year = datetime.datetime.now().strftime('%Y')               #
        try:                                                        #
            anniv = int(row['calc'])                                # eg. ccyy
        except Exception as e:                                      #
            anniv = 1900                                            #
            msg = f"error: {e}"                                     #
            logIt(msg)                                              #
        diff1 = int(year) - anniv + 1                               #
        allText = allText[:temp] + str(diff1) + allText[temp+7:]    #
    temp = allText.find('+ccyy+')                                   # LOGIC-8
    if (temp != -1):                                                # if +ccyy+ was found...
        year = datetime.datetime.now().strftime('%Y')               #
        allText = allText[:temp] + str(year) + allText[temp+6:]     #
    return allText, imgSrc                                          #

#
#   output xml
#
def output_xml(row, mmdd, slot):
    allText, imgSrc = process_data(row)                             #
    escText = html.escape(allText)                                  # LOGIC-9
    comment = row['comment']                                        #
    escComm = html.escape(comment)                                  #
    calc = row['calc']                                              #
    print('Content-Type: text/xml; charset=utf-8')                  # we're returning an XML response
    print('')                                                       # end of HTTP header
    print('<?xml version="1.0" encoding="utf-8"?>')                 # start of XML content
    print('<result>')                                               # user-defined by me (see JavaScript)
    print('<status>1</status>')                                     #
    print(f'<debug>{mmdd}</debug>')                                 # the parameter passed in
    print(f'<comment>{escComm}</comment>')                          #
    print(f'<calc>{calc}</calc>')                                   #
    print(f'<src>{imgSrc}</src>')                                   #
    print(f'<text>{escText}</text>')                                #
    print(f'<slot>{slot}</slot>')                                   #
    print('</result>')                                              #
#
#   output json
#
def output_json(row, mmdd, slot):
    allText, imgSrc = process_data(row)                             # cook the data
    print('Content-Type: text/json; charset=utf-8')                 # we're returning an XML response
    print('')                                                       # end of HTTP header
    del row['text3']                                                # remove raw
    del row['text2']
    del row['text1']
    row['imgSrc'] = imgSrc                                          # append cooked
    row['text'] = allText                                           # append cooked
    print(json.dumps(row, indent=1))                                # magic happens here
#
def output_plain(row, mmdd, slot):                                  #
    allText, imgSrc = process_data(row)                             #
    print('Content-Type: text/plain; charset=utf-8')                #
    print('')                                                       #
    print("debug  : " + mmdd)                                       #
    print("comment: " + row['comment'])                             # output: comment field
    print("calc   : " + row['calc'])                                #
    print("src    : " + imgSrc)                                     # output: IMG src field
    print("text   : " + allText)                                    # output: text fields

# ==============================================================
# main block
#
# example URLs:
# Dec-25) https://neilrieck.net/cgi-bin/daily_pix?mmdd=1225&xml=1
# Jan-01) https://neilrieck.net/cgi-bin/daily_pix?mmdd=0101&xml=1
# CO2   ) https://neilrieck.net/cgi-bin/daily_pix?mmdd=8000&xml=1
# ==============================================================
#
#   locate named data in cgi field storage
#
def getFld(cfs, label, dflt):
    if label not in cfs:
        return dflt
    else:
        return cfs.getvalue(label)

def main():
    cfs = cgi.FieldStorage()                                        # convert CGI data into a Python data
    xml = getFld(cfs, 'xml', '0')                                   # default to "0" if missing
    json = getFld(cfs, 'json', '0')                                 #
    slot = getFld(cfs, 'slot', '0')                                 # slot may be useful when caching an image
    mmdd = getFld(cfs, 'mmdd', '0212')                              # default to Charles Darwin's birthday
    try:
        x = int(mmdd)                                               #
        if (x < 0):                                                 #
            mmdd = "0000"                                           #
        if (x > 9999):                                              #
            mmdd = "9999"                                           #
    except Exception:                                               #
        mmdd = "0212"                                               #
    #
    #   start by logging this event (default privs may not allow this)
    #   caveat: if SELinux is enabled then we may need to write to /var/log
    #
    try:
        snap = datetime.datetime.now()                              # snapshot of the current time
        date = snap.strftime('%Y%m%d')                              #
        fn = f"dp-log/dp_{date}.txt"                                # all logs go into a daily file
        f = open(fn, "a")                                           #
        dt = snap.strftime('%Y%m%d%H%M%S')                          #
        f.write(f"time: {dt}\r\n")                                  #
        f.write(f"mmdd: {mmdd} xml: {xml} json: {json})\r\n")       #
        f.close()                                                   #
    except Exception as e:                                          #
        msg = f"error: {e} in logger"                               #
        logIt(msg)                                                  #
        pass                                                        #
    #
    row = get_record(mmdd)                                          # fetch one record from our database
    #
    # return data in the requested format
    #
    if (json == "1"):
        output_json(row, mmdd, slot)                                # output JSON data
    elif (xml == "1"):
        output_xml(row, mmdd, slot)                                 # output xml data
    else:
        output_plain(row, mmdd, slot)                               # output plain data

#
#   catch-all
#
if __name__ == '__main__':
    main()
#
# === end-of-file

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 Neil Rieck
 Waterloo, Ontario, Canada.