List of Criteria for Media Type Filtering
The table below lists and explains some important criteria for media type filtering. For each of these criteria, information is provided in the columns of the table as follows:
-
Criteria — Name of the criteria
-
Data format — Format of the data that the criteria relates to, for example, string or MIME type
-
Evaluated attributes — Attributes of a file or other web object, for example, the file name extension or the magic bytes, that are evaluated to find its media type
- Remarks — Remarks on what to consider when using the criteria in a rule
| Criteria | Data format | Evaluated attributes | Remarks |
|---|---|---|---|
| Ensured media types | List of MIME types | Magic bytes and other signatures | When this criteria is processed, the result is a list of media types in MIME type format, which are found by evaluating the magic bytes and other signatures of a file or other web object. A file or other web object can be of more than only one media type. If more than one media type is found, all of them are included in the list. If only one media type is found, the list includes only one item. A media type must be ensured with a high probability for a file or other web object to be included in the list. Not all files or other web objects have magic bytes and other signatures that can be used to ensure their media types with a high probability. If you want to cover these as well, you need to configure other criteria in addition to Ensured media types for your media type filtering rules, for example, the Non ensured media types criteria. The magic bytes and other signatures of a file or other web object can be evaluated in the different cycles of the filtering process, for example, as follows:
|
| Non ensured media types | List of MIME types | Attributes of a file or other web object | This criteria works in a way that is similar to how Ensured media types works. It works differently regarding the level of probability that is needed to ensure a media type. The result of processing this criteria is a list of media types in MIME format. But even if there is only a low probability that a file or other web object is of a particular media type, this is sufficient to include this media type in the list. |
| Media type from header | MIME type | Content type specified in request or response header | When this criteria is processed, the result is a media type in MIME format, which is found by evaluating the Content-Type header of a request or response. The Content-Type header can be evaluated in the different cycles of the filtering process, for example, as follows:
|
| Media type from extension | MIME type | Attributes of a file or other web object | When this criteria is processed, the result is a media type in MIME format for a file or other web object. To find this media type, the following is performed:
The attributes that are needed here can be evaluated, in the same way as for Body file name, within the request and response cycles. |
| Body file name | String | 1. File name 2. Content disposition specified in request or response header 3. part of URL path after last / |
When this criteria is processed, the result is a file name in string format. To find this name, the following is performed:
The file and the URL can be evaluated in the request cycle. The Content-Disposition header can be evaluated in both the request and response cycles. |
| File extension | String | Attributes of a file or other web object | When this criteria is processed, the result is a file name extension in string format. To find this extension, the following is performed:
The attributes that are needed here can be evaluated, in the same way as for Body file name, within the request and response cycles. |
| Is media type archive | Boolean | Magic bytes and other signatures | When this criteria is processed, the result is a Boolean value, either TRUE or FALSE. To find this value, the following is performed:
The attributes that are needed here can be evaluated, in the same way as for Ensured media types, within the request and response cycles and also within the embedded object cycles for requests and responses.
|