Validity Checks using Clojure
source link: https://blog.knoldus.com/validity-checks-using-clojure/
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Validity Checks using Clojure
For putting Validation checks using Clojure code, clojure noir library checks are used.
One needs to first create a form page using basic html for placing the checks.As an Example here, I am using a registration page text boxes to put the validation checks over the required fields.
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<label for="id">
{% if id-error %}<div>{{id-error}}</div>{% endif %}<input id="id" name="id" placeholder="User Name" type="text" value={{id}}></input></label>
<label for="email">
{% if id-error %}<div>{{email-error}}</div>{% endif %}<input id="email" name="email" placeholder="Email" type="text" value={{email}}></input></label>
<label for="pass">
{% if pass-error %}<div>{{pass-error}}</div>{% endif %}<input id="pass" name="pass" placeholder="Password" type="password" value={{pass}}></input></label>
<label for="confirmPass">
{% if confirmPass-error %}<div>{{confirmPass-error}}</div>{% endif %}<input id="confirmPass" name="confirmPass" placeholder="Confirm Password" type="password" value={{confirmPass}}></input></label>
Then we move ahead by creating a register.clj file where all validations are defined under the namespace definition:
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(ns projectName.routes.register
(:use compojure.core)
(:require
[noir.session :as session]
[noir.response :as resp]
[noir.validation :as vali])
Next is to create the route that defines the register function which is called when the register page is rendered.
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(defroutes register-routes
(GET "/register" []
(register))
the above route calls the following function:
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(defn register [& [id]]
(layout/render
"register.html"
{:id id:id-error (vali/on-error :id first)
:email-error (vali/on-error :email first)
:pass-error (vali/on-error :pass first)
:confirmPass-error (vali/on-error :confirmPass first)}))
where, [id] for any number of arguments passed, (layout/render) renders with that html page where validations are required to be placed, :id-error/email-error are variables placed in the html form that will define the error block, (vali/on-error) denotes noir validation structure.
Next step is to define the errors and put checks over the required fields i.e; defining the errors for above created check blocks.
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(defn valid? [id email pass confirmPass]
(vali/rule (vali/has-value? id)
[:id "Username is required"])
(vali/rule (vali/is-email? email)
[:email "Invalid Email Address"])
(vali/rule (vali/min-length? id 8)
[:id "Username must be at least 8 characters long"])
(vali/rule (vali/min-length? pass 8)
[:pass "Password must be at least 8 characters long"])
(vali/rule (= pass confirmPass)
[:confirmPass "Passwords does not match"])
(not (vali/errors? :id :email :pass :confirmPass)))
Joseph Ross is a Principal Consultant at Knoldus Inc. having more than 10 years of experience. Joseph has a passion for identifying challenges and give impactful solutions to the clients. He is a football fan and loves to watch TV series. Joseph has a cross-functional business operations and technology consulting experience. Joseph is familiar with programming languages such as Scala, C++, Java, CSS and HTML.
Written by Joseph Ross
Joseph Ross is a Principal Consultant at Knoldus Inc. having more than 10 years of experience. Joseph has a passion for identifying challenges and give impactful solutions to the clients. He is a football fan and loves to watch TV series. Joseph has a cross-functional business operations and technology consulting experience. Joseph is familiar with programming languages such as Scala, C++, Java, CSS and HTML.
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