Post Weather Forecast to Slack Regularly

I created a script to post weather forecast to Slack everyday, with Google Apps Script. It can be configured to post only specific weekdays.

Direction

Get forecast information from Open Weather Map.
Write script with CoffeeScript.
Post to Slack using Incoming WebHooks.
Post automatically using Google Apps Script.

Preparation

Get url of Incoming Webhooks in Slack.

Code

Open Weather Map become to require API Key. The following code is old, so please modify if you use it.

First, prepare CoffeeScript like the following. If you want to copy the following code, change Slack url to one that you configured.

It is CoffeeScript code, so it work as JavaScript mostly, but UrlFetchApp, Utilities is Google Apps object.

Temparature =
AbsoluteZeroDegree: -273.15
City =
Tokyo:
Id: 1850147
TimeZone: '+09:00'
SlackUrl =
incoming:
bot: 'https://hooks.slack.com/services/THIS/IS/EXAMPLE'
class WeatherAPIGateway
instance = null
class _WeatherAPIGatewayCore
url_base = 'http://api.openweathermap.org/data/2.5/weather'
tmp_json = null
getWeatherByCityId: (id) ->
url = url_base + '?id=' + id
return @.getWeatherJSONByUrl(url)
getWeatherJSONByUrl: (url) ->
webGateway = WebGateway.getInstance()
jsonString = webGateway.getBody(url)
return new Weather(Utilities.jsonParse(jsonString))
getDetailUrlByCityId: (id) ->
return 'http://openweathermap.org/city/id?=' + id
@getInstance: () ->
instance ?= new _WeatherAPIGatewayCore()
class Weather
_json = null
constructor: (json) ->
_json = json
getImageUrl: () ->
return 'http://openweathermap.org/img/w/' +
_json.weather[0].icon + '.png'
getTempertureInCelcius: () ->
return _json.main.temp + Temparature.AbsoluteZeroDegree
getMinimumTemparetureInCelcius: () ->
minimumTemparature = _json.main.temp_min + Temparature.AbsoluteZeroDegree
minimumTemparature = Math.round(minimumTemparature * 100) / 100
return minimumTemparature
getMaximumTemparatureInCelcius: () ->
maximumTemparature = _json.main.temp_max + Temparature.AbsoluteZeroDegree
maximumTemparature = Math.round(maximumTemparature * 100) / 100
return maximumTemparature
getCityName: ->
return _json.name
getTitle: ->
return _json.weather[0].main
getDescription: ->
return _json.weather[0].description
getWindSpeed: ->
return _json.wind.speed
getUnixTime: ->
return _json.dt
class SlackPushMessage
_message = {}
setText: (text) ->
_message['text'] = text
return @
getText: ->
return _message['text']
setUserName: (user_name) ->
_message['username'] = user_name
return @
getUserName: ->
return _message['user_name']
setIconUrl: (icon_url) ->
_message['icon_url'] = icon_url
return @
getIconUrl: ->
return _message['icon_url']
setMarkDown: (trueOrFalse) ->
_message['mrkdwn'] = trueOrFalse
return @
getMarkDown: ->
return _message['mrkdwn']
toJson: ->
return JSON.stringify(_message)
class SlackGateway
instance = null
class _SlackGateway
push: (url, payload) ->
webGateway = WebGateway.getInstance()
webGateway.post(url, payload)
@getInstance: ->
return instance ?= new _SlackGateway()
class WebGateway
instance = null
class _WebGateway
getBody: (url) ->
UrlFetchApp.fetch(url).getContentText()
post: (url, payload) ->
options =
method: 'post'
payload: payload
UrlFetchApp.fetch(url, options)
@getInstance: ->
return instance ?= new _WebGateway()
class PushWeatherToSlackService
instance = null
class _PushWeatherToSlackService
pushToSlack: (city) ->
# generate weather object
weatherAPIGateway = WeatherAPIGateway.getInstance()
weather = weatherAPIGateway.getWeatherByCityId(city.Id)
# create slack push message
message = new SlackPushMessage()
message.setUserName(
'Tokyo Weather Forecast at ' +
Utilities.formatDate(
new Date(weather.getUnixTime() * 1000), 'GMT' + city.TimeZone,
'yyyy-MM-dd HH:mm'))
message.setIconUrl(weather.getImageUrl())
message.setText(
'*' + weather.getTitle() + '* (' + weather.getDescription() + ')n' +
'Temp Range: ' + weather.getMinimumTemparetureInCelcius() + '-' +
weather.getMaximumTemparatureInCelcius() + ' °;Cn' +
'Wind: ' + weather.getWindSpeed() + ' m/sn' +
'<' + weatherAPIGateway.getDetailUrlByCityId(city.Id) + '|More Detail>' )
# push to slack
slackGateway = SlackGateway.getInstance()
slackGateway.push(
SlackUrl.incoming.bot, message.toJson())
@getInstance: ->
return instance ?= new _PushWeatherToSlackService()
###
execute
###
pushWeatherToSlackService = PushWeatherToSlackService.getInstance()
pushWeatherToSlackService.pushToSlack(City.Tokyo)

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Temparature =

AbsoluteZeroDegree: -273.15

City =

Tokyo:

Id: 1850147

TimeZone: '+09:00'

SlackUrl =

incoming:

bot: 'https://hooks.slack.com/services/THIS/IS/EXAMPLE'

class WeatherAPIGateway

instance = null

class _WeatherAPIGatewayCore

url_base = 'http://api.openweathermap.org/data/2.5/weather'

tmp_json = null

getWeatherByCityId: (id) ->

url = url_base + '?id=' + id

return @.getWeatherJSONByUrl(url)

getWeatherJSONByUrl: (url) ->

webGateway = WebGateway.getInstance()

jsonString = webGateway.getBody(url)

return new Weather(Utilities.jsonParse(jsonString))

getDetailUrlByCityId: (id) ->

return 'http://openweathermap.org/city/id?=' + id

@getInstance: () ->

instance ?= new _WeatherAPIGatewayCore()

class Weather

_json = null

constructor: (json) ->

_json = json

getImageUrl: () ->

return 'http://openweathermap.org/img/w/' +

_json.weather[0].icon + '.png'

getTempertureInCelcius: () ->

return _json.main.temp + Temparature.AbsoluteZeroDegree

getMinimumTemparetureInCelcius: () ->

minimumTemparature = _json.main.temp_min + Temparature.AbsoluteZeroDegree

minimumTemparature = Math.round(minimumTemparature * 100) / 100

return minimumTemparature

getMaximumTemparatureInCelcius: () ->

maximumTemparature = _json.main.temp_max + Temparature.AbsoluteZeroDegree

maximumTemparature = Math.round(maximumTemparature * 100) / 100

return maximumTemparature

getCityName: ->

return _json.name

getTitle: ->

return _json.weather[0].main

getDescription: ->

return _json.weather[0].description

getWindSpeed: ->

return _json.wind.speed

getUnixTime: ->

return _json.dt

class SlackPushMessage

_message = {}

setText: (text) ->

_message['text'] = text

return @

getText: ->

return _message['text']

setUserName: (user_name) ->

_message['username'] = user_name

return @

getUserName: ->

return _message['user_name']

setIconUrl: (icon_url) ->

_message['icon_url'] = icon_url

return @

getIconUrl: ->

return _message['icon_url']

setMarkDown: (trueOrFalse) ->

_message['mrkdwn'] = trueOrFalse

return @

getMarkDown: ->

return _message['mrkdwn']

toJson: ->

return JSON.stringify(_message)

class SlackGateway

instance = null

class _SlackGateway

push: (url, payload) ->

webGateway = WebGateway.getInstance()

webGateway.post(url, payload)

@getInstance: ->

return instance ?= new _SlackGateway()

class WebGateway

instance = null

class _WebGateway

getBody: (url) ->

UrlFetchApp.fetch(url).getContentText()

post: (url, payload) ->

options =

method: 'post'

payload: payload

UrlFetchApp.fetch(url, options)

@getInstance: ->

return instance ?= new _WebGateway()

class PushWeatherToSlackService

instance = null

class _PushWeatherToSlackService

pushToSlack: (city) ->

# generate weather object

weatherAPIGateway = WeatherAPIGateway.getInstance()

weather = weatherAPIGateway.getWeatherByCityId(city.Id)

# create slack push message

message = new SlackPushMessage()

message.setUserName(

'Tokyo Weather Forecast at ' +

Utilities.formatDate(

new Date(weather.getUnixTime() * 1000), 'GMT' + city.TimeZone,

'yyyy-MM-dd HH:mm'))

message.setIconUrl(weather.getImageUrl())

message.setText(

'*' + weather.getTitle() + '* (' + weather.getDescription() + ')n' +

'Temp Range: ' + weather.getMinimumTemparetureInCelcius() + '-' +

weather.getMaximumTemparatureInCelcius() + ' °;Cn' +

'Wind: ' + weather.getWindSpeed() + ' m/sn' +

'<' + weatherAPIGateway.getDetailUrlByCityId(city.Id) + '|More Detail>' )

# push to slack

slackGateway = SlackGateway.getInstance()

slackGateway.push(

SlackUrl.incoming.bot, message.toJson())

@getInstance: ->

return instance ?= new _PushWeatherToSlackService()

###

execute

###

pushWeatherToSlackService = PushWeatherToSlackService.getInstance()

pushWeatherToSlackService.pushToSlack(City.Tokyo)

If you write the code without creating class, it may be more short code.

After creating CoffeScript, compile it to JavaScript and copy it to Google Apps Script like the following.

function execute() {
// paste JavaScript here
}

function execute() {

// paste JavaScript here

}

Put the generated JavaScript into execute function. And choose execute function as the function to be executed first. If you want to execute and post weather forecast regularly, click menu, Resource and Current Project’s Triggers and configure when to post data to slack.

The above is posting to slack. You can also send data to mail, an example is written in the article, “Send Mail Automatically“. If you want to execute procedure only on business day, look at the articke “Process only on Business Day“.