Weather

Since Camel 2.12

Both producer and consumer are supported

The Weather component is used for polling weather information from Open Weather Map - a site that provides free global weather and forecast information. The information is returned as a json String object.

Camel will poll for updates to the current weather and forecasts once per hour by default. It can also be used to query the weather api based on the parameters defined on the endpoint which is used as producer.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-weather</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI format

weather://<unused name>[?options]

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists all the options, firstly for the component followed by the endpoint.

Component Options

The Weather component supports 3 options, which are listed below.

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

boolean

Endpoint Options

The Weather endpoint is configured using URI syntax:

weather:name

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

name (common)

Required The name value is not used.

String

Query Parameters (40 parameters)

Name Description Default Type

appid (common)

Required APPID ID used to authenticate the user connected to the API Server.

String

headerName (common)

To store the weather result in this header instead of the message body. This is useable if you want to keep current message body as-is.

String

language (common)

Language of the response.

Enum values:

  • en

  • ru

  • it

  • es

  • sp

  • uk

  • ua

  • de

  • pt

  • ro

  • pl

  • fi

  • nl

  • fr

  • bg

  • sv

  • se

  • zh_tw

  • zh

  • zh_cn

  • tr

  • hr

  • ca

WeatherLanguage

mode (common)

The output format of the weather data.

Enum values:

  • HTML

  • JSON

  • XML

WeatherMode

period (common)

If null, the current weather will be returned, else use values of 5, 7, 14 days. Only the numeric value for the forecast period is actually parsed, so spelling, capitalisation of the time period is up to you (its ignored).

String

units (common)

The units for temperature measurement.

Enum values:

  • IMPERIAL

  • METRIC

WeatherUnits

weatherApi (common)

The API to use (current, forecast/3 hour, forecast daily, station).

Enum values:

  • Current

  • Station

  • Hourly

  • Daily

WeatherApi

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

boolean

sendEmptyMessageWhenIdle (consumer)

If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

  • InOptionalOut

ExchangePattern

pollStrategy (consumer (advanced))

A pluggable org.apache.camel.PollingConsumerPollingStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel.

PollingConsumerPollStrategy

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

geoLocationProvider (advanced)

A custum geolocation provider to determine the longitude and latitude to use when no location information is set. The default implementaion uses the ipstack API and requires geolocationAccessKey and geolocationRequestHostIP.

GeoLocationProvider

httpClient (advanced)

To use an existing configured http client (for example with http proxy).

CloseableHttpClient

cnt (filter)

Number of results to be found.

Integer

ids (filter)

List of id’s of city/stations. You can separate multiple ids by comma.

String

lat (filter)

Latitude of location. You can use lat and lon options instead of location. For boxed queries this is the bottom latitude.

String

location (filter)

If null Camel will try and determine your current location using the geolocation of your ip address, else specify the city,country. For well known city names, Open Weather Map will determine the best fit, but multiple results may be returned. Hence specifying and country as well will return more accurate data. If you specify current as the location then the component will try to get the current latitude and longitude and use that to get the weather details. You can use lat and lon options instead of location.

String

lon (filter)

Longitude of location. You can use lat and lon options instead of location. For boxed queries this is the left longtitude.

String

rightLon (filter)

For boxed queries this is the right longtitude. Needs to be used in combination with topLat and zoom.

String

topLat (filter)

For boxed queries this is the top latitude. Needs to be used in combination with rightLon and zoom.

String

zip (filter)

Zip-code, e.g. 94040,us.

String

zoom (filter)

For boxed queries this is the zoom. Needs to be used in combination with rightLon and topLat.

Integer

backoffErrorThreshold (scheduler)

The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.

int

backoffIdleThreshold (scheduler)

The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.

int

backoffMultiplier (scheduler)

To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured.

int

delay (scheduler)

Milliseconds before the next poll.

long

greedy (scheduler)

If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.

boolean

initialDelay (scheduler)

Milliseconds before the first poll starts.

long

repeatCount (scheduler)

Specifies a maximum limit of number of fires. So if you set it to 1, the scheduler will only fire once. If you set it to 5, it will only fire five times. A value of zero or negative means fire forever.

long

runLoggingLevel (scheduler)

The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.

Enum values:

  • TRACE

  • DEBUG

  • INFO

  • WARN

  • ERROR

  • OFF

LoggingLevel

scheduledExecutorService (scheduler)

Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool.

ScheduledExecutorService

scheduler (scheduler)

To use a cron scheduler from either camel-spring or camel-quartz component. Use value spring or quartz for built in scheduler.

Object

schedulerProperties (scheduler)

To configure additional properties when using a custom scheduler or any of the Quartz, Spring based scheduler.

Map

startScheduler (scheduler)

Whether the scheduler should be auto started.

boolean

timeUnit (scheduler)

Time unit for initialDelay and delay options.

Enum values:

  • NANOSECONDS

  • MICROSECONDS

  • MILLISECONDS

  • SECONDS

  • MINUTES

  • HOURS

  • DAYS

TimeUnit

useFixedDelay (scheduler)

Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details.

boolean

geolocationAccessKey (security)

Required The geolocation service now needs an accessKey to be used.

String

geolocationRequestHostIP (security)

Required The geolocation service now needs to specify the IP associated to the accessKey you’re using.

String

Exchange data format

Camel will deliver the body as a json formatted java.lang.String (see the mode option above).

Message Headers

Header Description

CamelWeatherQuery

The original query URL sent to the Open Weather Map site

CamelWeatherLocation

Used by the producer to override the endpoint location and use the location from this header instead.

Samples

In this sample we find the 7 day weather forecast for Madrid, Spain:

from("weather:foo?location=Madrid,Spain&period=7 days&appid=APIKEY&geolocationAccessKey=IPSTACK_ACCESS_KEY&geolocationRequestHostIP=LOCAL_IP").to("jms:queue:weather");

To just find the current weather for your current location you can use this:

from("weather:foo?appid=APIKEY&geolocationAccessKey=IPSTACK_ACCESS_KEY&geolocationRequestHostIP=LOCAL_IP").to("jms:queue:weather");

And to find the weather using the producer we do:

from("direct:start")
  .to("weather:foo?location=Madrid,Spain&appid=APIKEY&geolocationAccessKey=IPSTACK_ACCESS_KEY&geolocationRequestHostIP=LOCAL_IP");

And we can send in a message with a header to get the weather for any location as shown:

String json = template.requestBodyAndHeader("direct:start", "", "CamelWeatherLocation", "Paris,France&appid=APIKEY", String.class);

And to get the weather at the current location, then:

String json = template.requestBodyAndHeader("direct:start", "", "CamelWeatherLocation", "current&appid=APIKEY", String.class);

Spring Boot Auto-Configuration

When using weather with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-weather-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 4 options, which are listed below.

Name Description Default Type

camel.component.weather.autowired-enabled

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

Boolean

camel.component.weather.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.weather.enabled

Whether to enable auto configuration of the weather component. This is enabled by default.

Boolean

camel.component.weather.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean