NiFi provides several different Processors out of the box for extracting Attributes from FlowFiles. A list of commonly used Processors for this purpose can be found above in the Attribute Extraction section. This is a very common use case for building custom Processors, as well. Many Processors are written to understand a specific data format and extract pertinent information from a FlowFile's content, creating Attributes to hold that information, so that decisions can then be made about how to route or process the data.