Send SMS from Chatter Feed with Action Link Template — Beyond Cloud

In Salesforce when you add an attachment in standard UI, content type of the uploaded file will be automatically detected by the browser. But when you create an attachment in Apex, ContentType is mandatory if attachment body is specified, and it will throw a run time error “FIELD_INTEGRITY_EXCEPTION ContentType is required if Body is specified” . […]

via Valid Values for ContentType in Salesforce — Tech from A to Z