# Wolfram Mathematica

## Cache a Popular Weather Summary Webpage

If a Delayed cloud object is viewed by many people before it needs to be recomputed, its output can be cached for a period of time through the CachePersistence option.

Define a function that computes temperature history for Rio de Janeiro the past week.

show complete Wolfram Language input
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rioTemperatureHistory[] := With[{temps = AirTemperatureData[ GeoPosition[ Entity["City", {"RioDeJaneiro", "RioDeJaneiro", "Brazil"}]], {Now - Quantity[1, "Weeks"], Now}]}, labelcolor = GrayLevel[0.4]; tempcolor = GrayLevel[0.4]; grid = Grid[{{Style["Current", labelcolor], Row[{Style[ QuantityForm[Round@Last[temps["Values"]], "Abbreviation"], tempcolor], " "}]}, {Style["High", labelcolor], Row[{Style[ QuantityForm[Round@Max[temps["Values"]], "Abbreviation"], tempcolor], " "}]}, {Style["Low", labelcolor], Row[{Style[ QuantityForm[Round@Min[temps["Values"]], "Abbreviation"], tempcolor], " "}]}}, Alignment -> {{Right, Left}}]; table = Style[Column[{Row[{"Past Week "}, Alignment -> {Bottom, Right} ], grid}, Alignment -> Right], 16, RGBColor[ 0.9098049191388243, 0.3176450101594796, 0.24313742164725222`]]; DateListPlot[temps, PlotRange -> {55, 100}, AxesLabel -> Style["\[Degree]F", 20, Black], TicksStyle -> Directive[Black, 14], Ticks -> {None, Automatic}, PlotStyle -> Directive[AbsoluteThickness[2], Black], Filling -> Bottom, FillingStyle -> Directive[RGBColor[ 0.9098049191388243, 0.3176450101594796, 0.24313742164725222`], Opacity[1]], Epilog -> Inset[table, Scaled[{0.95, 0.9}], {Right, Top}], PlotTheme -> {"Wide", "Presentation"}, ImageSize -> 550]] rioTemperatureHistory[]
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Deploy the function as an application that caches its result for 5 minutes. Now thousands of users can access the application and get reasonably up-to-date information without the server having to recompute the result every time, resulting in better response time and lower server load.

In[2]:=
obj = CloudDeploy[ Delayed[rioTemperatureHistory[], "PNG", CachePersistence -> Quantity[5, "Minutes"]]]
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