URI Template - extracting data

uri-template-extracting.md

Extracting Data Through URI Templates

the following list is far from complete. It just lists what I could immediately think of…

Templates that cannot be used for extracting values:

• http://example.com/{foo}{bar}
• http://example.com/{foo,bar}
• http://example.com/{?foo*}{&bar*}
• ?one=alpha&two=bravo ~ ?two=bravo&one=alpha - while they are different URIs by way of RFC 3986, most web applications neither differentiate them, nor enforce one or the other. Since applications (usually) don't fail on "wrong parameter order", developers tend to handle this rather lax

Derived rules of non-extractability

1. Multi-Variable-Expressions: {var1,var2}

• OK: foo,bar -> {var1: "foo", var2: "bar"}
• FAIL: foo,bar,baz -> {var1: ["foo", "bar"], var2: "baz"} or {var1: "foo", var2: ["bar", "baz"]} or {var1: ["foo", "bar", "baz"], var2: null} or {var1: null, var2: ["foo", "bar", "baz"]}

2. Expression sequence: {var1}{var2}

• no-matter the input, {var2} would always end up null or empty

3. Exploded Query String expressions