holyjak

;; Put this inside your blog and use the clojure CLI instead of leiningen to run `clojure -X:serve`
{:deps {org.clojure/clojure {:mvn/version "1.10.1"}
        ring-server/ring-server {:mvn/version "0.5.0"}
        ring/ring-devel {:mvn/version "1.7.1"}
        compojure/compojure {:mvn/version "1.6.1"}
        #_#_cryogen-core/cryogen-core {:mvn/version "0.3.2"}
        cryogen-asciidoc/cryogen-asciidoc {:mvn/version "0.3.2"}
        cryogen-flexmark/cryogen-flexmark {:mvn/version "0.1.4"}
        cryogen-core/cryogen-core {:git/url "https://github.com/cryogen-project/cryogen-core" :sha "17cdf3837f17b9b921dce09e4638495984e65a2a"}
        }

holyjak

Spring 4 - 404 troubleshooting

See https://www.baeldung.com/spring-handler-mappings - explains BeanNameUrlHandlerMapping, SimpleUrlHandlerMapping

Debug DispatcherServlet - DispatcherServlet.getHandler

• this.handlerMappings - I have 5 incl. (each has a pathMatcher: AntPathMatcher https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/util/AntPathMatcher.html which has . match(String pattern, String path))
  • RequestMappingHandlerMapping,
    • mappingRegistry.urlLookup and .mappingLookup -> controller methods
  • BeanNameUrlHandlerMapping,
• handlerMap (empty)

holyjak

;; catching-transduce - works most of the time but blocks forever in some case(s)
;; If I interrupt it, it is at line 26, i.e. inside `(a/<!! errors-ch)`
;; inside core.async ... CountDownLatch.await
(with-test
  (defn catching-transduce
    "Similar to `core.async/transduce` but returns the reduced value and
  captures 'anomalies' (i.e. exceptions sent as data) in the `chan` data and
  captures exceptions in `xf` and `f`, stopping at the first one.

  Returns the result or throws if there was any anomaly / exception."

holyjak

Update: This has now been published at https://blog.jakubholy.net/2020/error-handling-in-fulcro/

I present three ways of detecting, handling, and showing server-side errors: globally and at the component level.

By default, Fulcro considers only non-200 HTTP status as an error. It is up to you to tell it what is an error and how to handle it.

This is somewhat controversial - as Programming with Pure Optimism in the Fulcro Developers Guide explains:

A server should not throw an exception and trigger a need for error handling unless there is a real, non-recoverable situation.

holyjak

Source code for my Telia Full Stack Feast talk "Want more from your frontend framework!" (slides) (6/2020), comparing Redux with REST and a Fulcro with Pathom (Graph API).

Use case we are implementing: Show “hot deals” in your webshop, loaded on-demand.

PS: For the sake of simplicity I am cheating a little and presenting the Fulcro HotDeals component as a root component. If it was used as a child, we would need to either change the a Link Query or make sure that the :deals are presented as a property on the parent component. Also, I use unqualified keys for brevity. This is not recommended in practice.

holyjak

Fulcro Field Notes

Assorted notes from learning and experimenting with Fulcro.

My blog posts

• Using React.forwardRef in Fulcro (and rendering a Fulcro component from a JS one)

• and couple more…​

Learning tips

holyjak

I am making a PoC of an app with a number of linked "reports" (mostly master-detail). Some of the features I will need:

• Ability to sort the tables by one or multiple columns
• Ability to filter the tables (e.g. "only show people from Norway")
• Pagination
• Eventually allow the user to hide some columns (and remember this for the user, e.g. in a cookie / localStorage / server)

As far as I know, fulcro-rad does not support that yet so here are some thoughts about how this could be configured.

holyjak

Solution

L14 is wrong, it should have been wrapped in {..} and thus a join: :query [{:people [(comp/get-query Person)]}]

holyjak

Solution

There are 2 problems:

1. L14 should have been {:query [:people (comp/get-query Person)]
2. L15 mixes the template and lambda forms; it should have been either

:initial-state (fn [_] {:people [(comp/get-initial-state Person {:id 0 :name "Sally" :city "Nowhere" :state "GA"})
 (comp/get-initial-state Person {:id 1 :name "Tom" :city "There" :state "OH"})]}

holyjak

#!/usr/bin/env python3
# See https://gist.github.com/teasherm/bb73f21ed2f3b46bc1c2ca48ec2c1cf5
import argparse
import os

import boto3


class S3MultipartUpload(object):
  # AWS throws EntityTooSmall error for parts smaller than 5 MB