4.2.2.15. HTTP Client Gateway In – Babelway

The HTTP client gateway IN allows you to periodically retrieve the responses to a sequence of one or more HTTP calls.

You can schedule these runs though the Properties > Scheduling section. This will allow you to configure schedules such as "run every weekday at noon EST".

HTTP Flow

The sequence of calls that you want to run is called the HTTP flow. The flow is editable in the "HTTP flow" tab of your gateway. Each call of the flow is represented by a separate box and they are chained according to the order of the calls as determined in the tab "Next Step":

Each call has a set of individual properties:

Request

The Request of the call is defined by the

- HTTP method one uses to call the URL and

- the URL itself.

Your API documentation should indicate which method to use depending on what you are trying to do with that URL. Fetching data will usually involve a "GET" request. Modifying data will use "POST" or "PATCH". Creating data might require using the "PUT" HTTP method.

The URL of your request can be either a constant (URL is used as written in text in the field), one based on metadata (in that case, it will be treated as a constant where all text between curly brackets will be replaced by its matching metadata value - this is not as meaningful in a HTTP client IN), or a script if you wish to compute the URL using JavaScript.

Authorization

In this tab you will either set up a specific authorization for this call or you will choose to use the one you set up for your whole flow. See the "Authentication" article for more information on setting up your authentication.

Headers

This tab allows you to add specific headers to your request. Any headers you add here will override default settings for those headers if they exist.

Body

When issuing a call, you can modify the content of the body in this tab.

Post Result

The post result is the set of actions you want to take based on the result of your call. This is where you can configure the creation of a message, the extraction of metadata, or running additional scripts for example. You can add any or all of the below actions:

Create Babelway Message	This is the most common post result action. It allows you to produce a Babelway message. You will define - the content of the message: the result of the call is contained in responseContent. This variable is accessible through script and can be parsed to extract only a subset of the response data. - creation condition: When completed, the message creation will only happen when this evaluates to true - response filename: This will become the file name of your message in. - set metadatas: this allows you to extract metadata to attach to this new message. - connected gateways: by default, the message created will be generated in the current gateway. With this option, you can opt to push the message into another channel. - user metadata transfer strategy: If you are in a gateway out, or if you have collected a large amount of metadata not all of which ought to be transferred to the child message, then you can configure here, which metadata to keep.
Additional response validation	This allows to configure additional checks after the call completes. - success condition: If this evaluates to true, the run is deemed successful. - error message: If the success condition is not met, then this error message will be displayed in the gateway's runtime information.
Extract Variable	This allows one to extract variables that can then be used in scripts.
Extract Metadata	This allows one to attach metadata that can be used later in the call or in the subsequently created messages.
Set User comment of the Babelway Message	Babelway messages have a "user comment". This action allows to set its value.
Set Gateway In/Out Message Key	Babelway messages have a gateway in message key. This action allows to set it for messages created by the gateway.

Next Step

The "Next Step" tab allows you to configure the next step of the flow after successful execution of all the requirements of your current call. Steps are identified by their name. The name can be hardcoded. In that case, select "constant" and write it in.

If you've stored information that allows you to compute the name through a metadata, select metadata. For example, perhaps you have a sequence of calls like this: "fetchProduct1", "fetchProduct2", "fetchProduct3", "fetchProduct4". You have saved the product number in a metadata.

If you need any more elaborate logic to compute your next step, then use the "script" option. Note that since you are in a script, you need to provide a string value for your next step.

Beware that you must provide a string value for all possible cases and an empty string for no further action. Thus, the else "" is important!

if(responseCode == 404) "callBertrand" else ""

When "Next step" is empty or blank, the execution will end and no other calls will be executed.

⚠️ If the "Next step" produces a name with a typo or that simply is not defined, then the run will fail.

Settings

Each call has a settings tab that will allow you to set up general properties for your call:

- Timeout: how long do we wait before we abandon the call?

- Valid HTTP Return Codes: This is a comma separated list of the return codes you wish to handle. Note that this doesn't necessarily mean that all these return codes are a successful run of the current call, simply that you want to handle the step after these codes. For example, this call could be requesting product information. A 404 code would indicate it doesn't exist yet. You could then have a next action that does this:

if(responseCode == 404) "createProduct" else "updateProduct"

In this case, although 404 is an error code it will be listed in your Valid HTTP Return Codes.