Using modules in crystal

By Maximilian Batz | 2019-01-22

As your application grows, you would like to move from one big .cr file to separating your code into smaller files. You can use require from your main .cr file to add code from other files: require “./tools/*” This statement will add code from the tools directory, relative to your main .cr file. This will…

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Exception: Unexpected quote at 1:2 (CSV::MalformedCSVError) Crystal

By Maximilian Batz | 2019-01-13

While trying to parse an Amazon pay file, I stumbled across this particular problem: Exception: Unexpected quote at 1:2 (CSV::MalformedCSVError) The reason: Amazon Pay encodes it’s files in UTF-8 with BOM. The BOM is an optional (in UTF-8 files) marker. You can see it with the tool xxd for instance xxd apolish_amazon_2018DecMonthlyTransaction.csv | less The…

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Install Crystal on Docker: how to add the Crystal repository to Docker in the Dockerfile

By Maximilian Batz | 2019-01-11

Dockerfile (excerpt) ENV APT_KEY_DONT_WARN_ON_DANGEROUS_USAGE=DontWarn RUN apt-get update && apt-get install -y \          software-properties-common \          build-essential \         libevent-dev \         libssl-dev \         libxml2-dev \         libyaml-dev \         libgmp-dev \         libreadline-dev \         apt-transport-https \         iputils-ping \         git \         aptitude \         nano \         openssh-server \         && apt-key adv –keyserver keys.gnupg.net –recv-keys 09617FD37CC06B54 \         && add-apt-repository ‘deb https://dist.crystal-lang.org/apt crystal…

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Crystal libevent-2.0.so.5: cannot open shared object file

By Maximilian Batz | 2019-01-05

Today I upgraded my Ubuntu to 18.04. Compiling a file with Crystal gives me the following error: stderr:     /root/.cache/crystal/usr-share-crystal-src-ecr-process.cr/macro_run: error while loading shared libraries: libevent-2.0.so.5: cannot open shared object file: No such file or directory The library in question, libevent-2.0.so.5 has been superseded by libevent-2.1.so.6 => /usr/lib/x86_64-linux-gnu/libevent-2.1.so.6 Crystal is of course aware of this…

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Crystal & Alpine on the Raspberry Pi

By Maximilian Batz | 2018-12-21

Bringing together two interesting technologies: Alpine Linux – a small-size and security oriented Linux distribution Crystal – a compiled language with a nice syntax (similar to Ruby) on the Raspberry Pi (armhf / ARMv6, which would also support the Pi Zero W) is not possible currently, as of 21.12.2018. There is no (at least no…

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Crystal: crystal language Duplicate trail found

By Maximilian Batz | 2018-12-13

max@morpheus:~/crystal/taxgod$ crystal run src/taxgod.cr Unhandled exception: Duplicate trail found ‘vat-correction’ (Radix::Tree::DuplicateError) from lib/radix/src/radix/tree.cr:0:11 in ‘add’ from lib/radix/src/radix/tree.cr:149:11 in ‘add’ from lib/radix/src/radix/tree.cr:149:11 in ‘add’ from lib/radix/src/radix/tree.cr:108:9 in ‘add’ from lib/kemal/src/kemal/route_handler.cr:49:7 in ‘add_to_radix_tree’ from lib/kemal/src/kemal/route_handler.cr:21:7 in ‘add_route’ from lib/kemal/src/kemal/dsl.cr:12:1 in ‘post’ from src/vatcorrection.cr:26:2 in ‘__crystal_main’ from /usr/share/crystal/src/crystal/main.cr:97:5 in ‘main_user_code’ from /usr/share/crystal/src/crystal/main.cr:86:7 in ‘main’ from /usr/share/crystal/src/crystal/main.cr:106:3 in ‘main’…

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