Using tsvector operators

[sumeetkh]

Hi,

I am trying to learn how to use tsvector operators in a graphql query, but not able to find documentation about it. Here's the corresponding sql query I am trying to run.

select * from table where text_search_vector @@ plainto_tsquery('search_string')

Is this doable with Hasura operators?

Thank you!

[BenoitRanque]

here is a list of supported postgres operators and their equivalent in graphql.
There is no currently available way to use tsvector with the api automatically provided by hasura.
This leaves you with a few options, the simplest of which is most likely table computed fields.
There is an open RFC for parametrized queries which will offer a more ergonomic solution in the future.
You can find it here

[sumeetkh]

Thanks for you response Benoit.

I looked into custom defined functions option - but it only solves the most basic use cases. Based on playing around with it, I am only able to send text arguments to the custom function and the graphql api does not interpret a boolean tsquery.

To get this to work on a general query would require a lot of string wrangling to get the query into a shape that would work.

I think if the RFC is implemented, it would certainly help for these use cases.

[BenoitRanque]

Note that even the RFC will not allow you to "interpret a boolean tsquery". That would effectively be SQL injection which is a security issue.
In both cases you would send one or more text arguments to search with, and craft an SQL query using those arguments to return your filtered data.

[sumeetkh]

Got it, thanks Benoit. In that case, in the absence of first class support for text search operators https://www.postgresql.org/docs/10/functions-textsearch.html in the query language, doing non-trivial search over the graphql api becomes really hard.

E.g. a interpreting a boolean expression with multiple clauses in the custom function, "term1" && ("term2" || "term3")

[BenoitRanque]

I'm not sure I understand. You can pass multiple arguments to the custom function. You could even pass arrays if the quantity of arguments of X type is unknown.

[sumeetkh]

Yeah, I found about variadic arguments support in postgres custom functions - so the use case is doable for now. It still requires a fair bit of manipulation that I'd have liked to avoid, but it works for now.