Search API - HTTP Query Argument Format

I've created a search API for a site that I work on. For example, some of the queries it supports are:

• /api/search - returns popular search results
• /api/search?q=car - returns results matching the term "car"
• /api/search?start=50&limit=50 - returns 50 results starting at offset 50
• /api/search?user_id=3987 - returns results owned by the user with ID 3987

These query arguments can be mixed and matched. It's implemented under the hood using Solr's facete开发者_JAVA技巧d search.

I'm working on adding query arguments that can filter results based on a numeric attribute. For example, I might want to only return results where the view count is greater than 100. I'm wondering what the best practice is for specifying this.

Solr uses this way:

/api/search?views:[100 TO *]

Google seems to do something like this:

/api/search?viewsisgt:100

Neither of these seem very appealing to me. Is there a best practice for specifying this kind of query term? Any suggestions?

Simply use ',' as separator for from/to, it reads the best and in my view is intuitive:

# fixed from/to
/search?views=4,2

# upper wildcard
/search?views=4,

# lower wildcard
/search?views=,4

I take values inclusive. In most circumstances you won't need the exclusive/inclusive additional syntax sugar.

Binding it even works very well in some frameworks out of the box (like spring mvc), which bind ',' separated values to an array of values. You could then wrap the internal array with specific accessors (getMin(), getMax()).

Google's approach is good, why it's not appealing?

Here comes my suggestion:

/api/search?viewsgt=100

I think the mathematical notation for limits are suitable.

[x  the lower limit can be atleast x
x]  the upper limit can be atmost x
(x  the lower limit must be strictly greater than x
x)  the upper limit must be strictly lesser than x

Hence,

q=cats&range=(100,200) - the results from 100 to 200, but not including 100 and 200
q=cats&range=[100,200) - the results from 100 to 200, but the lower limit can be greater than 100
q=cats&range=[100 - any number from 100 onwards
q=cats&range=(100 - any number greater than 100
q=cats&range=100,200 - default, same as [100,200] 

Sure, its aesthetics are still questionable, but it seems (IMO) the most intuitive for the human eye, and the parser is still easy.

As per http://en.wikipedia.org/wiki/Percent-encoding =,&,[,],(,) are reserved