React - Trying to Changing <img> src attribute - reactjs

Question

I'm trying to change the src attribute of an element after an AJAX call to a database. I have a default image url defined in getDefaultProps(), but after the AJAX call the image doesn't change.
PictureWidget is a child component of a Section component that controls the state (it also passes dataSource and dataSourceParams to PictureWidget). I'm not sure if I can use a local state for PictureWidget so I'm trying to do it through props.
This is my code:
var PictureWidget = React.createClass({
getDefaultProps: function() {
return {
url: 'https://d2o57arp16h0eu.cloudfront.net/echo/img/no_image_available.png'
}
},
componentDidMount: function() {
this.componentDidUpdate();
},
componentDidUpdate: function() {
// Grab img URL from DB
var postData = {
dataSource: this.props.params.dataSource,
dataSourceParams: this.props.dataSourceParams
};
$.ajax({
type: 'POST',
url: ajax_endpoint,
cache: false,
data: postData,
dataType: 'json',
success: function(response) {
if (response.data.length > 0) {
this.updateImage(response.data[0][0]);
}
}.bind(this),
error: function(response) {
this.render();
}
});
},
updateImage: function(url) {
console.log("Updating props.url with " + url);
this.props.url = url;
this.render();
},
render: function(imageURL) {
console.log("Rendering img " + this.props.url);
return React.createElement('div', {className: ' pure-u-' + this.props.columns},
React.createElement('div', {className: 'picture-widget'},
React.createElement('img', {src: this.props.url})
)
)
}
});
And this is my console log (forgive me for the poor formatting, still new to Overflow):
Rendering img https://d2o57arp16h0eu.cloudfront.net/echo/img/no_image_available.png
Updating props.url with http://vignette3.wikia.nocookie.net/animalcrossing/images/4/49/Tumblr_lvrcmvCpsS1qbeyouo1_500.jpg/revision/latest
Rendering img http://vignette3.wikia.nocookie.net/animalcrossing/images/4/49/Tumblr_lvrcmvCpsS1qbeyouo1_500.jpg/revision/latest
The initial render() grabs the default URL, but after the AJAX call this.props.url does get updated to the new value, so I would suspect React.createElement('img', {src: this.props.url}) is the trouble maker. Can I not update the src attribute this way?

Answer 1

This is what state is for. Try using getInitialState instead of getDefaultProps and bind url to this.state using setState().
getInitialState: function() {
return {
url: 'https://d2o57arp16h0eu.cloudfront.net/echo/img/no_image_available.png'
};
},
updateImage: function(url) {
console.log("Updating state.url with " + url);
this.setState({ url: url });
}