Every company need to have its own merchant code and encryption key,
thus it is not possible to use environment variables to keep that data,
and i have to store it in the database.
I do not want to give SELECT permission on the encryption key to guest,
because i am going to fuck it up sooner or later, and everyone would be
able to read that secret; i know it would. Therefore, i need a security
definer function that takes the data to encrypt, use the key to encrypt
it, and returns the result; nobody else should have access to that key,
not even admins!
By the way, i found out that every merchant receives the same key, thus
it is not a problem to keep it in the repository.
Since i need that SQL function to encrypt the data, i thought that i may
go the whole nine yards and sign the request in PostgreSQL too, after
all the data to sign comes from there, and it has JSON functions to
create and base64-code an object.
Fortunately, pg_crypto has all the functions that i need, but i can no
longer keep that extension inside the auth schema, because it is used
from others, and the public schema, like every other extensions, seems
more appropriate.
Instead of having the list of currency and language codes that Redsys
uses as constants in the code, i moved that as field to the currency
and language relations, so i can simply pass the lang_tag to the
function and it can transform that tag to the correct code; the currency
is from the company’s relation, since it is the only currency used in
the whole application (for now).
As a consequence, i had to grant execute to currency and the parse_price
functions to guest, too.
To generate the test data used in the unit tests, i used a third-party
PHP implementation[0], but i only got from that the resulting base64-coded
JSON object and signature, using the same that as in the unit test, and
did not use any code from there.
PostgreSQL formats the JSON as text differently than most
implementations i have seen: it adds spaces between the key name and
the colons, and space between the value and the separating comma. The
first implementation used replace() to format the JSON as exactly as
the PHP implementation, so that the result matches, and then tried to do
generate the form by hand using the output from PostgreSQL without the
replace(), to verify that Redsys would still accept my input. Finally,
i adjusted the unit test to whatever pg_prove said it was getting from
the function.
I still have the form’s action hard-codded to the test environment, but
the idea is that administrators should be able to switch from test to
live themselves. That means that i need that info in the redsys
relation as well. I think this is one of the few use cases for SQL’s
types, because it is unlikely to change anytime soon, and i do not need
the actual labels.
Unfortunately, i could not use enumerations for the request’s
transaction type because i can not attach an arbitrary number to the
enum’s values. Having a relation is overkill, because i would need
a constant in Go to refer to its primary key anyway, thus i kept the
same constant i had before for that. Language and currency constant
went out, as this is in the corresponding relations.
In setup_redsys i must have a separate update if the encrypt_key is null
because PostgreSQL checks constraints before key conflict, and i do
not want to give a default value to the key if the row is not there yet.
The problem is that i want to use null to mean “keep the same password”,
because it is what i intend to do with the user-facing form: leave the
input empty to keep the same password.
As now Go needs to pass composite types back and forth with PostgreSQL,
i need to register these types, and i have to do it every time because
the only moment i have access to the non-pooled connection is in the
AfterConnect function, but at that point i have no idea whether the
user is going to request a payment. I do not know how much the
performance degrades because of this.
[0]: https://github.com/ssheduardo/sermepa/blob/master/src/Sermepa/Tpv/Tpv.php
The idea is that the booking form will be prefilled with the values
passed from that other mini-form, and the campsite type is implicit
due to the page where the form is located at, but i need to give it to
the booking page.
The booking page does not yet use that information.
The form is based on the one in the current website, but in a single
page instead of split into many pages; possibly each <fieldset> should
be in a separate page/view. The idea is for Oriol to check the design
and decide how it would be presented to the user, so i needed something
to show him first.
I hardcoded the **test** data for the customer’s Redsys account. Is
this bad? I hope not, but i am not really, really sure.
The data sent to Redsys is just a placeholder because there are booking
details that i do not know, like what i have to do with the “teenagers”
field or the area preferences, thus i can not yet have a booking
relation. Nevertheless, had to generate a random order number up to
12-chars in length or Redsys would refuse the payment, claiming that
the order is duplicated.
The Redsys package is based on the PHP code provided by Redsys
themselves, plus some hints at the implementations from various Go
packages that did not know why they were so complicated.
Had to grant select on table country to guest in order to show the
select with the country options.
I have changed the “Postal code” input in taxDetails for “Postcode”
because this is the spell that it is used in the current web, i did not
see a reason to change it—it is an accepted form—, and i did not want to
have inconsistencies between forms.
Oriol does not want to waste so much vertical space for the calendar,
and wants it to show in a carousel, initially with only 6 months, and
loading the next three each time the user scrolls past the last.
I now use HTMx in the public page too for this auto-loading behavior,
based on their “infinite scroll” example[0].
Had to put the /calendar URI inside campsites because in the
calendar.gohtml i do not know the current type’s UUID, and can not use
a relative URL to “add subdirectories”, because the type does not end
with a slash.
Had to change season.CollectCalendar to expect the first month and a
number of months to show, to be able to load only 6 or 3 months after
the current, for the initial carousel content, or after the last month
of the carousel.
[0]: https://htmx.org/examples/infinite-scroll/
I had to export the Calendar type from Season to use it from
campsite/types, and also renamed them because season.SeasonCalendar is
a bit redundant compared to just season.Calendar.
I still have not added the HTMx code to switch year because i am not
sure whether Oriol will want to show a whole year or just half a year.
The calculation for the text color taking into account the contrast with
the background is from [0].
[0]: https://www.smashingmagazine.com/2020/07/css-techniques-legibility/#foreground-contrast
In the old website, the prices where show with all the options, but in
the new design only a single price is show, that in the case of
campsites with options is the price per night of the “base” plus the
minimum options selected.
I want these because when there are changes in the signature i then have
to find where it is used, and it is easier to do when the compiler tells
you.
For relations it is less necessary because GoLand knows how to validate
SQL strings for them, but it seems to not work with functions,
apparently due to the lack of the “FROM” keyword.
Besides, it tx.FunctionName(ctx, params...) is shorter than
tx.Exec("select functions_name($1, $2…)", params...).
This is the text that introduces the carousel; it is not a spiel, but
this is what i call it.
It turns out that this text needs to have paragraphs and headings, much
like home’s slider, rather than the one in services page, thus no need
to change its font size or to align all items in the carousel in the
middle.
I can not reuse the carousel package because these carousels need the
campsite site’s slug as a first parameters: i can not have a relation
per campsite type, as i do in home and services pages, because the
campsite types are added by administration types; even if i had a
single relation for slides of home and services pages, these would go
in a different relation due to the foreign key to campsite type.
What i could reuse, however, is the Slide and SlideEntry types from
that package, although i had to export carousel.Translation to be usable
from the types package. I should change that to use locale.Translation,
but this was the easier option, or i would need to change the queries
and templates for carousel package too.
Besides that, they work exactly like the slides in home and services
pages.
I created a common template to show the company address in the footer
and the contact page, and then i realized Go did not like to output my
phone URL in the anchor without having the tel: schema in the template.
I then removed that variable and now the URL is created with tel: and
the phone number with its spaces removed.
I was not sure whether to use PostGIS to store the GPS location of the
company, as i am sure i will only use that point just to show the map.
However, just in case, it is not a big deal.
There is no way to change that from the administration pages for now,
because of time constraints, and it is very unlikely that they will
change the campgrounds’ location in the near future.
The location is in a separate table because i did not want to have to
change every test file, to be honest, but this also makes the map
“optional” without the need for NULL values.
I added the contact address to every public page because the new design
adds it to the footer, so i will be needing it everywhere, just like the
menu.
Since i have my browser in English, the automatically detected language
is also set in English, making it harder for me to see if i added all
the translations; when the language is Catalan, i can see the
untranslated strings.
This calendar is supposed to be edited by admin users, but do not yet
have the complete JavaScript code to do so, thus for now i have made it
read-only.
I just found out that this is a feature introduced in PostgreSQL 10,
back in 2017.
Besides this being the standard way to define an “auto incremental
column” introduced in SQL:2003[0], called “identity columns”, in
PostgreSQL the new syntax has the following pros, according to [1]:
* No need to explicitly grant usage on the generated sequence.
* Can restart the sequence with only the name of the table and column;
no need to know the sequence’s name.
* An identity column has no default, and the sequence is better
“linked” to the table, therefore you can not drop the default value
but leave the sequence around, and, conversely, can not drop the
sequence if the column is still defined.
Due to this, PostgreSQL’s authors recommendation is to use identity
columns instead of serial, unless there is the need for compatibility
with PostgreSQL older than 10[2], which is not our case.
According to PostgreSQL’s documentation[3], the identity column can be
‘GENERATED BY DEFAULT’ or ‘GENERATED ALWAYS’. In the latter case, it is
not possible to give a user-specified value when inserting unless
specifying ‘OVERRIDING SYSTEM VALUE’. I think this would make harder to
write pgTAP tests, and the old behaviour of serial, which is equivalent
to ‘GENERATED BY DEFAULT’, did not bring me any trouble so far.
[0]: https://sigmodrecord.org/publications/sigmodRecord/0403/E.JimAndrew-standard.pdf
[1]: https://www.2ndquadrant.com/en/blog/postgresql-10-identity-columns/
[2]: https://wiki.postgresql.org/wiki/Don't_Do_This#Don.27t_use_serial
[3]: https://www.postgresql.org/docs/15/sql-createtable.html
I do not like confirmation messages: they question user’s actions, and
in general it is better to offer an undo option afterward. However, undo
is harder to implement, and currently i do not have time to do this.
The delete for the session is different because the only repercussion
would be to log in again; the user is not in danger of losing any data
whatsoever.
jordi fita mas