Use Case Description
I have an integer multiplication web service exposed over HTTP, and want to make it accessible via email, where emails containing the input data sent to a predefined address are processed and replied to with the multiplication results.
Solution
UltraESB-X can be configured to proxy messages between the email service and the web service in order to enable the acceptance of data from and propagation of results to email senders.
Prerequisites
The following connectors and processing elements should be selected when creating an Ultra project for our requirement (or added to the project later via Tools → Ultra Studio → Component Registry):
-
Mail Connector (for both ingress (listener) and egress (sender))
-
NIO HTTP Connector (for sending HTTP requests to the web service)
-
Transport Header Manager (for some header manipulations)
Implementation
-
Add the following
Mapfor use in enabling SSL for IMAP (email polling) as well as SMTP (email sending), inproject.xpml:Type
MapName
mail-propsmail.imap.ssl.enabletruemail.smtp.starttls.enabletrue -
Add a Mail Ingress Connector to accept incoming multiplication request emails, with the following configuration (assuming a Gmail account):
Basic
Protocol
imapHost
imap.gmail.comPort
993User
Password
your-passwordFolder
INBOXOther Settings
mail-props (Map)Processing
Preserve Headers (1)
FromLazy-fetch Payload (2)
OffLazy-fetch Attachments (3)
OnScheduling
Polling Start Delay
2000Polling Repeat Interval
10000(1) avoids fetching of unnecessary email headers, as we would be submitting the message to an HTTP endpoint later on
(2) we want the payload, so fetch it eagerly
(3) we don’t expect attachments, and will not be accessing them even if they are present
-
Add an Add Variable processing element to extract the value of the retained
Fromheader (sender’s email address) into arecipientvariable:Variable Name
recipientExtraction Type
HEADERValue
FromVariable Type
String -
Add a NIO HTTP Egress Connector to forward the received request to the multiplication web service:
Basic
Destination Address type
URLDestination Host
localhostDestination Port
9000Service Path
/service/JsonServlet -
Add an Add New Transport Header processing element to set the subject of the response email:
Transport Header Name
mail.subjectUse Variable
OffValue
Multiplication ResultHeader Variable Type
String -
Restore the previously saved sender’s email address from
recipientvariable into themail.totransport header, using another Add New Transport Header processing element:Transport Header Name
mail.toUse Variable
OnValue
recipientHeader Variable Type
String -
Finally, add a Mail Egress Connector to send the response back to the sender (assuming a Gmail account):
Basic
Protocol
smtpHost
smtp.gmail.comPort
25User
Password
your-passwordOther Settings
mail-props
The final flow would resemble the following:
Testing
-
A multiplication service that accepts JSON payloads in the format
{"v1":first_number,"v2":second_number}is available in the Jetty Server plugin shipped with Ultra Studio. Click View → Tool Windows → Jetty Server and click the green start button to start a Jetty server at port 9000. (If you have run a server instance previously, it will be listed in the Jetty Servers list, in which case you should start the corresponding (port 9000) server from the list.) -
Create a new UltraESB Server runtime configuration, and start the project.
-
Send an email to
your-email@gmail.comcontaining a multiplication request in the message body, such as the following:{"v1":7,"v2":6} -
A response email will be delivered to the account from which you sent the multiplication request, resembling:
{"result":42,"v1":7,"v2":6}
Property Configuration
When running the sample in the UltraESB-X distribution, you need to override the following properties in-order for the sample to work.
| Refer to Managing Project Properties documentation on how to override properties. |
|
Email account of the user who accepts input data |
|
Email password of the user who accepts input data |
|
Email account of the user who sends back computed data |
|
Email password of the user who sends back computed data |
| Depnding on the email provider which hosts the emails that you have mentioned above, you may have to enable insecure application access in account settings |
In this topic
In this topic