remove user and password from DSN record

[akdor1154]

Hey,
This PR removes auth stuff from the DSN record of the Connection struct. Instead it is passed in at connection time them forgotten. Two rationales:

• the password is sensitive information and it's really easy at the moment to have it printed by mistake to e.g. notebook output.
• allows to standardize the (dsn; user, pass) method to work on both DSN names and raw connection strings

Additionally, it allows me to add an extraauth parameter which is appended as-is and likewise treated as sensitive info. This will be database specific, and could be used for e.g. auth tokens, Snowflake warehouse specification, etc etc, basically things for where my code's connection string needs to be the same per-user, but users may still need to put account-specific config to get a DB connection. (This model actually follows how PowerBI models ODBC connections, and I figure that they have done a bit more solution design across different DBs than I have :) )

Added public API:

function Connection(dsn::AbstractString; user=nothing, password=nothing, extraauth=nothing)

Tests added and checked against MariaDB locally (we'll see what Travis says).. I will do further testing if Travis passes.

Any and all feedback welcome, this is my first public work in Julia so there are probably style issues at the very least.

[codecov]

Codecov Report

Merging #305 into master will increase coverage by 0.17%.
The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master     #305      +/-   ##
==========================================
+ Coverage   78.24%   78.42%   +0.17%     
==========================================
  Files           6        6              
  Lines         754      760       +6     
==========================================
+ Hits          590      596       +6     
  Misses        164      164              

Impacted Files	Coverage Δ
src/dbinterface.jl	93.67% <87.50%> (+0.22%)	⬆️
src/API.jl	67.35% <100.00%> (ø)

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[quinnj]

I'm in favor of these changes. It seems you're probably still working on stuff right now, right? For example, I don't see the user/password fields removed from the Connection struct yet?

The extraauth stuff seems fine to me as well. I get a little nervous changing some of that stuff just because (as you may know) differences between drivers can be pretty finicky. But in general, the changes you have there look fine.

Just ping me here once you think this is ready to review/merge!

[quinnj]

This is more escaping that we had before! So I say we run w/ this for now; the nice thing is that people can always just pass the whole connection string themselves if they want.

[akdor1154]

woop. I did have one thought on this - my change is technically a breaking change for any user who is currently passing their password manually like connect(dsn, "root", "{im escaping my pwd myself}"). Do you have any thoughts on that? it's a bit of an edge case and I can't see any issues discussing it so maybe no-one has hit it yet.

[akdor1154]

thanks for the response, yep I had finished at that point but will fix up your review points in a little bit.

I am a bit confused by

I don't see the user/password fields removed from the Connection struct yet?

Have I missed/misunderstood something? I preserved

Connection(dsn::AbstractString, usr, pwd) = Connection(dsn; user=usr, password=pwd)

to not break your API but as far as i can tell user and password never actually end up in the Connection struct (they are used to create the dbc from API.Connect/SQLDriverConnect I guess)

[quinnj]

Looks good; thanks!