bcquality/microsoft/knowledge/web-services/handle-httpclient-platform-failure-before-response-access.md

bc-version	domain	keywords	technologies	countries	application-area
all	web-services	httpclient transport-failure boolean-return httpresponsemessage content runtime-error	al	w1	all

Handle HttpClient platform failure before accessing the response

Description

AL HttpClient methods can fail before a usable HTTP response exists because of an invalid request, DNS or network failure, certificate validation, timeout, a disabled extension setting, or the response-size limit. When code captures the optional Boolean return value, false reports this platform or transport failure. The accompanying HttpResponseMessage is not safe to consume; accessing its content after the failed call can raise another error and obscure the original failure.

Best Practice

When capturing the Boolean return value from Get, Post, Put, Delete, or Send, stop the current response-processing path immediately when it is false. Report or propagate the transport failure without reading status, headers, or content. Omitting the optional Boolean is also valid when fail-fast behavior is intended: the runtime then raises an error if the operation cannot execute.

See sample: handle-httpclient-platform-failure-before-response-access.good.al.

Anti Pattern

Capturing a failed call in a Boolean and then reading Response.Content(), parsing the body, or otherwise treating Response as usable. Do not report omission of the Boolean by itself; that form deliberately delegates failure propagation to the runtime.

See sample: handle-httpclient-platform-failure-before-response-access.bad.al.

References

• HttpClient.Send method
• Call external services with HttpClient