Open APIs

Hello Community,
When implementing Attribute Filtering in various TMF OpenAPIs, I noticed a few things when using the various comparison operators.

Chapter 4.4 of the TMF630 Guidelines Part 1 describes a number of operators.

1. one of the two variants for the use of operators provides the format <Key><UrlEncodedOperatorSymbol><Value>.

For example: /entity?quantity%3E5 for "quantity > 5".

If I interpret the RFC3986 correctly, such a string is allowed. It seems to me that some tools have a hard time with query parameters that do not match the key=value scheme.
Is there any experience from others here?

2. Looking at the "Operator literal" and "URL Encoded form" columns in chapter 4.4, I found a discrepancy.
The regex operator is described as *= which is converted to %2A%3D. But in the guide it says %3D~ which then corresponds to =~. Which variant is the correct one?

For equality: Is the operator == via %3D%3D necessary at all? After all, a consumer can also use key=value or should we still provide ==?

I would appreciate any hints and thank you in advance for your answers.

Regards,

Jan

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Jan Lemmermann
OSS Lead Architect
EWE TEL GmbH
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Hi Jan, I can only comment on (1) - my experience tells me that most tools/frameworks allow you to extract the entire query part as defined by the RFC (basically, characters between ? and either # or the end of the URL) because it's really not a given that queries always follow the key=value&... pattern. That also means you very likely have to parse the actual expression in the application, the same way you would if the expression were enclosed in a dedicated parameter (for the sake of an example, if it were ?s=quantity%3E5, you would still end up parsing the expression stored in s). I also guess that == is used instead of = to avoid any confusion between comparison and assignment.

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Alexey Rusakov
Red Hat, Inc.
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