Hello,
I am using web2py to monitor and control an instrument. I am
dynamically generating plots using matplotlib following the DNA
application example from SC2009 (http://www.web2py.com/examples/static/
sc/sc_dna_talk.pdf)
I was able to get the basic aspects working based on that example.
However, I want to automatically display new plots as new data is
available. I am using the following code in the view:
<script>
var auto_refresh = setInterval(
function()
{
$('#loaddiv').load('statusbox.load');
$('#threshpng').html('<img src="/myapp/default/dataThreshPlot.png">');
}, 5000);
</script>
<div id="loaddiv">loading...</div>
<div id="threshpng">png loading</div>
The statusbox.load generates a table with some statistics about the
data, and this successfully updates every 5 seconds as desired.
However, the dataThreshPlot never gets refreshed, only the initial
version is displayed. (a timestamp is written to the plot when it is
generated so I can verify this fact).
If I simply browse to localhost:8000/myapp/default/dataThreshPlot.png
the plot is properly generated and displayed each time I refresh the
page.
I have tried adding this code to the dataThreshPlot function in the
controller:
response.headers['Expires'] = time.strftime("%a, %d %b %Y %H:%M:%S
+0000", time.gmtime(time.time()+1))
to try to avoid caching, but still no luck.
I also tried making a very simple controller function as follows:
def dataThreshPage():
return dict(threshim= URL(r=request,f=dataThreshPlot))
and view:
<img src={{=threshim}}>
and tested that localhost:8000/myapp/default/dataThreshPage presents
the plot as expected.
I then modified the jquery refresh code to:
<script>
var auto_refresh = setInterval(
function()
{
$('#loaddiv').load('statusbox.load');
$('#threshpng').load('/myapp/default/dataThreshPage');
}, 5000);
</script>
<div id="loaddiv">loading...</div>
<div id="threshpng">png loading</div>
but still no luck.
Any suggestions for how to get these plots to refresh?
Thank you,
G
