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MultiForm Module

Introduction

MultiForm is a SilverStripe module, allowing flow control for forms, and step process to be automatically determined based on configuration variables on each step class. It augments the existing Form class in SilverStripe.

The goal of the module is to allow greater flexibility than features, so each individual implementation can be customized to the project requirements.

Maintainer Contact

• Sean Harvey (Nickname: sharvey, halkyon) <sean (at) silverstripe (dot) com>
• Ingo Schommer (Nickname: chillu) <ingo (at) silverstripe (dot) com>

Requirements

• SilverStripe ^5.

Note: For a SilverStripe 4.x or 3.x compatible version, please use ^2 or ^1 tagged version

What it does do

• Abstracts fields, actions and validation to each individual step.
• Maintains flow control automatically, so it knows which steps are ahead and behind. It also can retrieve an entire step process from start to finish, useful for a step list.
• Persists data by storing it in the session for each step, once it's completed. The session is saved into the database.
• Allows customisation of next, previous steps, saving, loading and finalisation of the entire step process
• Allows for basic ability to branch a step by overloading the next step method with logic to switch based on a condition (e.g. a checkbox, or dropdown in the field data).
• Ties a user logged in who is using the step process (if applicable). This means you can build extended security or logging.
• Basic flexibility on the URL presented to the user when they are using the forms. By default it stores an encrypted hash of the session in the URL, but you can reference it by the ID instead. It's recommend that additional security, such as checking the user who first started the session be applied if you want to reference by ID.

What it doesn't do

• Automatically handle relation saving, e.g. MembershipForm manages the Member
• Provide a complete package out of the box (you must write a bit of code using the tutorial!)
• Automatically determine what to do at the end of the process, and where to save it
• Provide nicely presented URLs of each step (an enhancement, for the future)

Note: The multiform directory should sit in your SilverStripe root project directory in the file system as a sibling of cms and framework.

Reporting bugs

If you've found a bug that should be fixed for future releases, then please make a ticket on https://github.com/silverstripe/silverstripe-multiform/issues.

This helps to ensure we release less buggy software in the future!

Tutorial

The assumption is the developer who is starting this tutorial has an intermediate level of knowledge in SilverStripe, understands what "run dev/build?flush=1" means, and has written some custom PHP code in SilverStripe before.

If you are not familiar with SilverStripe, it is highly recommended you run through the tutorials before attempting to start with this one.

• View a listing of all available tutorials

1. Installing

Using Composer, you can install multiform into your SilverStripe site using this command (while in the directory where your site is currently located)

2. Create subclass of MultiForm

First of all, we need to create a new subclass of MultiForm.

For the above example, our multi-form will be called SurveyForm

3. Set up first step

Now that we've created our new MultiForm subclass step, we need to define what form is going to be the first step in our multi-step process.

Each form step must subclass MultiFormStep. This is so the multi-form can identify that this step is part of our step process, and is not just a standard form.

So, for example, if we were going to have a first step which collects the personal details of the form user, then we might have this class:

Now that we've got our first step of the form defined, we need to go back to our subclass of MultiForm, SurveyForm, and tell it that SurveyFormPersonalDetailsStep is the first step.

4. Define next step, and final step

We've managed to set up the basics of multi-form, but it's not very useful, as there's only one step!

To get more than one step, each step needs to know what it's next step is in order to use flow control in our system.

To let the step know what step is next in the process, we do the same as setting the $start_step variable SurveyForm, but we call it $next_steps.

At the very least, each step also has to have a getFields() method returning a FieldSet with some form field objects. These are the fields that the form will render for the given step.

Keep in mind that our multi-form also requires an end point. This step is the final one, and needs to have another variable set to let the multi-form system know this is the final step.

So, if we assume that the last step in our process is OrganisationDetailsStep, then we can do something like this:

5. Run database integrity check

We need to run dev/build?flush=1 now, so that the classes are available to the SilverStripe manifest builder, and to ensure that the database is up to date with all the latest tables. So you can go ahead and do that.

Note: Whenever you add a new step, you MUST run dev/build?flush=1 or you may receive errors.

However, we've forgotten one thing. We need to create a method on a page-type so that the form can be rendered into a given template.

So, if we want to render our multi-form as $SurveyForm in the Page.ss template, we need to create a SurveyForm method (function) on the controller:

The SurveyForm() function will create a new instance of our subclass of MultiForm, which in this example, is SurveyForm. This in turn will then set up all the form fields, actions, and validation available to each step, as well as the session.

You can of course, put the SurveyForm method on any controller class you like.

Your template should look something like this, to render the form in:

In this case, the above template example is a sub-template inside the Layout directory for the templates. Note that we have also included $Form, so standard forms are still able to be used alongside our multi-step form.

6. Adding a step indicator

By default, we include a couple of basic progress indicators which could be useful, out of the box.

Two of them, as of the time of writing this are:

• Progress list (multiform/templates/Includes/MultiFormProgressList.ss)
• Progress complete percent (multiform/templates/Includes/MultiFormProgressPercent.ss)

They are designed to be used either by themselves, or alongside each other. For example, the percentage could compliment the progress list to give an indication of completion status.

To include these with our instance of multiform, we just need to add an <% include %> statement into the template.

For example:

This means the included template is rendered within the scope of the SurveyForm instance returned, instead of the top level controller context. This gives us the data to show the progression of the steps.

Putting it together, we might have something looking like this:

Feel free to play around with the progress indicators. If you need something specific to your project, just create a new "Include" template inside your own project templates directory, and include that instead. Some helpful methods to use on the MultiForm would be:

• AllStepsLinear() (which also makes use of getAllStepsRecursive() to produce a list of steps)
• getCompletedStepCount()
• getTotalStepCount()
• getCompletedPercent()

The default progress indicators make use of the above functions in the templates.

To use a custom method of your own, simply create a new method on your subclass of MultiForm. In this example, SurveyForm would be the one to customise. This new method you create would then become available in the progress indicator template.

7. Loading values from other steps

There are several use cases where you want to pre-populate a value based on the submission value of another step. There are two methods supporting this:

• getValueFromOtherStep() loads any submitted value from another step from the session
• copyValueFromOtherStep() saves you the repeated work of adding the same lines of code again and again.

Here is an example of how to populate the email address from step 1 in step2 :

8. Finishing it up

Now that we've got a structure set up to collect form data along each step, and progress through successfully, we need to customise what happens at the end of the last step.

On the final step, the finish() method is called to finalise all the data from the steps we completed. This method can be found on MultiForm. However, we cannot automatically save each step, because we don't know where to save it. So, we must write some code on our subclass of MultiForm, overloading finish() to tell it what to do at the end.

Here is an example of what we could do here:

9. Organisation data model

The class Organisation is mentioned in the above example but doesn't exist at the moment (unlike the existing Member() class which looks after the member groups in SilverStripe) so we need to create it:

This example has been chosen as a separate DataObject but you may wish to change the code and add the data to the Member class instead.

Warning

If you're dealing with sensitive data, it's best to delete the session and step data immediately after the form is successfully submitted.

You can delete it by calling this method on the finish() for your MultiForm subclass:

This will also go through each of it's steps and delete them as well.

Customising

Because the multi-form system doesn't magically do everything for you, although it does provide a sensible set of defaults, it means you need to customise certain aspects of it. Here are some useful methods that can be customised (although you can technically overload anything available on MultiForm and MultiFormStep!):

Templates

The best part about this system is the freedom to customise each form step template.

In order, when you have a page with a multi-form rendering into it, it chooses which template to render that form in this order, within the context of the MultiForm class:

• $this->getCurrentStep()->class (the current step class)
• MultiFormStep
• $this->class (your subclass of MultiForm)
• MultiForm
• Form

More than likely, you'll want the first one to be available when the form renders. To that effect, you can start placing templates in the templates/Includes directory for your project. You need to name them the same as the class name for each step. For example, if you want MembershipForm, a subclass of MultiFormStep to have it's own template, you would put MembershipForm.ss into that directory, and run ?flush=1.

If you'd like a pre-existing template on how to customise the form step, have a look at Form.ss that's found within the framework module. Use that template, as a base for your new MembershipForm.ss template in your project templates.

For more information on this, please look at the Form documentation.

getNextStep()

If you are wanting to override the next step (for example if you want the next step to be something different based on a user's choice of input during the step) you can override getNextStep() on any given step to manually override what the next step should be. An example:

Validation

To define validation on a step-by-step basis, please define getValidator() and return a Validator object, such as RequiredFields - for more information on form validation see :form.

e.g.

finish()

finish() is the final call in the process. At this step, all the form data would most likely be unserialized, and saved to the database in whatever way the developer sees fit. By default, we have a finish() method on MultiForm which serializes the last step form data into the database, and that's it.

finish() should be overloaded onto your subclass of MultiForm, and parent::finish() should be called first, otherwise the last step form data won't be saved.

For example:

The above is a sample bit of code that simply fetches all the steps in the database that were saved. Further refinement could include getting steps only if the Data (serialized raw form data) is set, as the above example doesn't respect branching of steps (multiple next steps on a given form step).

Best practices

Delete session after submission

If you're dealing with sensitive data, such as credit card fields, or personal fields that shouldn't be lying around in the session database, then it's a good idea to immediately delete this data after the user has submitted.

This can be easily achieved by adding the following line at the end of your finish() method on your MultiForm subclass.

Expiring old session data

Included with the MultiForm module is a class called MultiFormPurgeTask. This task can be used to purge expired session data on a regular basis. The date of expiry can be customised, and is given a default of 7 days to delete sessions after their creation.

You can run the task from the URL, by using http://mysite.com/dev/tasks/MultiFormPurgeTask?flush=1

MultiFormPurgeTask is a subclass of BuildTask, so can be run using the SilverStripe CLI tools.

One way of automatically running this on a UNIX based machine is by cron.

TODO

• Code example on how to use $form->saveInto() with MultiForm, as it doesn't have all steps in the $form context at finish()

• Allowing a user to click a link, and have an email sent to them with the current state, so they can come back and use the form exactly where they left off

• Possibly allow for different means to persist data, such as the browser session cache instead of the database.

• Different presentation of the URL to identify each step.

• Allow customisation of prev() and next() on each step. Currently you can only customise for the entire MultiForm subclass. There is a way to customise on a per step basis, which could be described in a small recipe.

• More detailed explanation, and recipe example on how to make branched multistep forms. For example, clicking a different action takes you to an alternative next step than the one defined in $next_steps

Related

• Form

  • Form field types

• Tutorials

  • Tutorial 3 - Forms
• Templates