Call Django View from D3.js onclick event on Heatmap - django

Question

Is there a way to invoke a Django view and pass it a parameter(s) from a D3.js onclick event handler associated with a heatmap? For my heatmap, I'm using the code found at the following:
https://www.d3-graph-gallery.com/graph/heatmap_style.html
Any help would be greatly appreciated. Thanks.

Answer 1

This is javascript code, which makes HTTP request when click on rectangle. Use jquery library (I am using here, in this example $.ajax({}) is jQuery's function). You can use Javascript's XMLHttpRequest class also, to make AJAX call. You should just pass correct URL of Django's view. Also, use GET request for testing purposes to avoid CSRF Features of Django.
<script>
// set the dimensions and margins of the graph
var margin = {top: 80, right: 25, bottom: 30, left: 40},
width = 450 - margin.left - margin.right,
height = 450 - margin.top - margin.bottom;
// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform",
"translate(" + margin.left + "," + margin.top + ")");
//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/heatmap_data.csv", function(data) {
// Labels of row and columns -> unique identifier of the column called 'group' and 'variable'
var myGroups = d3.map(data, function(d){return d.group;}).keys()
var myVars = d3.map(data, function(d){return d.variable;}).keys()
// Build X scales and axis:
var x = d3.scaleBand()
.range([ 0, width ])
.domain(myGroups)
.padding(0.05);
svg.append("g")
.style("font-size", 15)
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x).tickSize(0))
.select(".domain").remove()
// Build Y scales and axis:
var y = d3.scaleBand()
.range([ height, 0 ])
.domain(myVars)
.padding(0.05);
svg.append("g")
.style("font-size", 15)
.call(d3.axisLeft(y).tickSize(0))
.select(".domain").remove()
// Build color scale
var myColor = d3.scaleSequential()
.interpolator(d3.interpolateInferno)
.domain([1,100])
// create a tooltip
var tooltip = d3.select("#my_dataviz")
.append("div")
.style("opacity", 0)
.attr("class", "tooltip")
.style("background-color", "white")
.style("border", "solid")
.style("border-width", "2px")
.style("border-radius", "5px")
.style("padding", "5px")
// Three function that change the tooltip when user hover / move / leave a cell
var mouseover = function(d) {
tooltip
.style("opacity", 1)
d3.select(this)
.style("stroke", "black")
.style("opacity", 1)
}
var mousemove = function(d) {
tooltip
.html("The exact value of<br>this cell is: " + d.value)
.style("left", (d3.mouse(this)[0]+70) + "px")
.style("top", (d3.mouse(this)[1]) + "px")
}
var mouseleave = function(d) {
tooltip
.style("opacity", 0)
d3.select(this)
.style("stroke", "none")
.style("opacity", 0.8)
}
// add the squares
svg.selectAll()
.data(data, function(d) {return d.group+':'+d.variable;})
.enter()
.append("rect")
.attr("x", function(d) { return x(d.group) })
.attr("y", function(d) { return y(d.variable) })
.attr("rx", 4)
.attr("ry", 4)
.attr("width", x.bandwidth() )
.attr("height", y.bandwidth() )
.style("fill", function(d) { return myColor(d.value)} )
.style("stroke-width", 4)
.style("stroke", "none")
.style("opacity", 0.8)
.on("mouseover", mouseover)
.on("mousemove", mousemove)
.on("mouseleave", mouseleave)
.on("click", function(arg1, arg2, arg3) {
console.log('clicked !!!');
// make AJAX call now !
$.ajax({
type: 'GET',
url: '<DJANGO_VIEW_URL_HERE>',
data: {'key1': 'val1', 'key2': 'val2'},
success: function(data) {
console.log('server returned status code 200');
},
error: function() {
console.log('problem on server during processing');
}
});
})
})
// Add title to graph
svg.append("text")
.attr("x", 0)
.attr("y", -50)
.attr("text-anchor", "left")
.style("font-size", "22px")
.text("A d3.js heatmap");
// Add subtitle to graph
svg.append("text")
.attr("x", 0)
.attr("y", -20)
.attr("text-anchor", "left")
.style("font-size", "14px")
.style("fill", "grey")
.style("max-width", 400)
.text("A short description of the take-away message of this chart.");
</script>
Good luck.