Support Typecasting Function Parameters (Postgis ST_Transform Bug)

I have come across a problem, with different solutions, but I would like to propose a feature that would allow the calling of functions to be typecasted in the parameterization.

First the code:

function ST_Transform(shape, srid)
    {
        let sridParam = '?';

        if (_.isNumber(srid))
        {
            sridParam += '::integer';
        }

        return knex.raw(`st_transform(?, ${sridParam})`, [shape, srid]);
    };

The Problem:

This is in a file called ‘postgis.js’ in my architecture. What it allows me to do is import postgis and call postgis.ST_Transform(geom, 4326). Originally this code was 1 line long that got wrapped up in a convenience function. That was until Postgis 2.3.0 dropped and they changed it so that ST_Transform now takes a string or an integer. This causes an error because parameterized raw statements do not get typecasted naturally.

The Solution:

If knex had a property that was .executeFunction() that:

• Took a string representation of a function name.
• An array of values to be passed in.
• An array of typecastings to be used.

It could be a very clean implementation for executing functions with correct types which has been requested multiple times from other issues. If we could start a discussion about a good way to accomplish this via code it would be appreciated and I would happily help with the implementation.

[cprieger]

Didn’t want to just disappear on this issue or have it go cold. I will try and get some work in this weekend on a good proposal for changes (maybe even a pull request Chronos willing).

But in defense of @elhigu point wrapping this in your own Knex.raw helper class works just as well.

This discussion is mainly for “Is there a clean implementation that could be adapted to meet Knex’s standards and fit the overall model?” Which is actually fairly non-trivial when consideration is given to the different databases, typecastings, and syntactic sugars that can take place.

[cprieger]

Sure. Give me a bit to work on it some more. I want to make sure I include the weird dichotomy between PLPGSQL and T-SQL function execution. So i’ll work up some good examples for you. Thanks for discussing this feature request.