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Adjusted punctuation and grammar for Form Helpers guide [ci skip]

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Brian Jordan 2014-06-23 16:54:06 -07:00 committed by Zachary Scott
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guides/source/form_helpers.md
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@ -276,7 +276,7 @@ The name passed to `form_for` controls the key used in `params` to access the fo
The helper methods called on the form builder are identical to the model object helpers except that it is not necessary to specify which object is being edited since this is already managed by the form builder.
You can create a similar binding without actually creating `<form>` tags with the `fields_for` helper. This is useful for editing additional model objects with the same form. For example if you had a `Person` model with an associated `ContactDetail` model you could create a form for creating both like so:
You can create a similar binding without actually creating `<form>` tags with the `fields_for` helper. This is useful for editing additional model objects with the same form. For example, if you had a `Person` model with an associated `ContactDetail` model, you could create a form for creating both like so:
```erb
<%= form_for @person, url: {action: "create"} do |person_form| %>
@ -534,7 +534,7 @@ Both of these families of helpers will create a series of select boxes for the d
### Barebones Helpers
The `select_*` family of helpers take as their first argument an instance of `Date`, `Time` or `DateTime` that is used as the currently selected value. You may omit this parameter, in which case the current date is used. For example
The `select_*` family of helpers take as their first argument an instance of `Date`, `Time` or `DateTime` that is used as the currently selected value. You may omit this parameter, in which case the current date is used. For example:
```erb
<%= select_date Date.today, prefix: :start_date %>
@ -548,7 +548,7 @@ outputs (with actual option values omitted for brevity)
<select id="start_date_day" name="start_date[day]"> ... </select>
```
The above inputs would result in `params[:start_date]` being a hash with keys `:year`, `:month`, `:day`. To get an actual `Date`, `Time` or `DateTime` object you would have to extract these values and pass them to the appropriate constructor, for example
The above inputs would result in `params[:start_date]` being a hash with keys `:year`, `:month`, `:day`. To get an actual `Date`, `Time` or `DateTime` object you would have to extract these values and pass them to the appropriate constructor, for example:
```ruby
Date.civil(params[:start_date][:year].to_i, params[:start_date][:month].to_i, params[:start_date][:day].to_i)
@ -591,9 +591,9 @@ NOTE: In many cases the built-in date pickers are clumsy as they do not aid the
### Individual Components
Occasionally you need to display just a single date component such as a year or a month. Rails provides a series of helpers for this, one for each component `select_year`, `select_month`, `select_day`, `select_hour`, `select_minute`, `select_second`. These helpers are fairly straightforward. By default they will generate an input field named after the time component (for example "year" for `select_year`, "month" for `select_month` etc.) although this can be overridden with the `:field_name` option. The `:prefix` option works in the same way that it does for `select_date` and `select_time` and has the same default value.
Occasionally you need to display just a single date component such as a year or a month. Rails provides a series of helpers for this, one for each component `select_year`, `select_month`, `select_day`, `select_hour`, `select_minute`, `select_second`. These helpers are fairly straightforward. By default they will generate an input field named after the time component (for example, "year" for `select_year`, "month" for `select_month` etc.) although this can be overridden with the `:field_name` option. The `:prefix` option works in the same way that it does for `select_date` and `select_time` and has the same default value.
The first parameter specifies which value should be selected and can either be an instance of a `Date`, `Time` or `DateTime`, in which case the relevant component will be extracted, or a numerical value. For example
The first parameter specifies which value should be selected and can either be an instance of a `Date`, `Time` or `DateTime`, in which case the relevant component will be extracted, or a numerical value. For example:
```erb
<%= select_year(2009) %>
@ -645,7 +645,7 @@ Unlike other forms making an asynchronous file upload form is not as simple as p
Customizing Form Builders
-------------------------
As mentioned previously the object yielded by `form_for` and `fields_for` is an instance of `FormBuilder` (or a subclass thereof). Form builders encapsulate the notion of displaying form elements for a single object. While you can of course write helpers for your forms in the usual way, you can also subclass `FormBuilder` and add the helpers there. For example
As mentioned previously the object yielded by `form_for` and `fields_for` is an instance of `FormBuilder` (or a subclass thereof). Form builders encapsulate the notion of displaying form elements for a single object. While you can of course write helpers for your forms in the usual way, you can also subclass `FormBuilder` and add the helpers there. For example:
```erb
<%= form_for @person do |f| %>
@ -684,12 +684,12 @@ If `f` is an instance of `FormBuilder` then this will render the `form` partial,
Understanding Parameter Naming Conventions
------------------------------------------
As you've seen in the previous sections, values from forms can be at the top level of the `params` hash or nested in another hash. For example in a standard `create`
As you've seen in the previous sections, values from forms can be at the top level of the `params` hash or nested in another hash. For example, in a standard `create`
action for a Person model, `params[:person]` would usually be a hash of all the attributes for the person to create. The `params` hash can also contain arrays, arrays of hashes and so on.
Fundamentally HTML forms don't know about any sort of structured data, all they generate is name-value pairs, where pairs are just plain strings. The arrays and hashes you see in your application are the result of some parameter naming conventions that Rails uses.
TIP: You may find you can try out examples in this section faster by using the console to directly invoke Racks' parameter parser. For example,
TIP: You may find you can try out examples in this section faster by using the console to directly invoke Rack's parameter parser. For example,
```ruby
Rack::Utils.parse_query "name=fred&phone=0123456789"
@ -698,7 +698,7 @@ Rack::Utils.parse_query "name=fred&phone=0123456789"
### Basic Structures
The two basic structures are arrays and hashes. Hashes mirror the syntax used for accessing the value in `params`. For example if a form contains
The two basic structures are arrays and hashes. Hashes mirror the syntax used for accessing the value in `params`. For example, if a form contains:
```html
<input id="person_name" name="person[name]" type="text" value="Henry"/>
@ -712,7 +712,7 @@ the `params` hash will contain
and `params[:person][:name]` will retrieve the submitted value in the controller.
Hashes can be nested as many levels as required, for example
Hashes can be nested as many levels as required, for example:
```html
<input id="person_address_city" name="person[address][city]" type="text" value="New York"/>
@ -724,7 +724,7 @@ will result in the `params` hash being
{'person' => {'address' => {'city' => 'New York'}}}
```
Normally Rails ignores duplicate parameter names. If the parameter name contains an empty set of square brackets [] then they will be accumulated in an array. If you wanted people to be able to input multiple phone numbers, you could place this in the form:
Normally Rails ignores duplicate parameter names. If the parameter name contains an empty set of square brackets `[]` then they will be accumulated in an array. If you wanted users to be able to input multiple phone numbers, you could place this in the form:
```html
<input name="person[phone_number][]" type="text"/>
@ -732,11 +732,11 @@ Normally Rails ignores duplicate parameter names. If the parameter name contains
<input name="person[phone_number][]" type="text"/>
```
This would result in `params[:person][:phone_number]` being an array.
This would result in `params[:person][:phone_number]` being an array containing the inputted phone numbers.
### Combining Them
We can mix and match these two concepts. For example, one element of a hash might be an array as in the previous example, or you can have an array of hashes. For example a form might let you create any number of addresses by repeating the following form fragment
We can mix and match these two concepts. One element of a hash might be an array as in the previous example, or you can have an array of hashes. For example, a form might let you create any number of addresses by repeating the following form fragment
```html
<input name="addresses[][line1]" type="text"/>
@ -746,7 +746,7 @@ We can mix and match these two concepts. For example, one element of a hash migh
This would result in `params[:addresses]` being an array of hashes with keys `line1`, `line2` and `city`. Rails decides to start accumulating values in a new hash whenever it encounters an input name that already exists in the current hash.
There's a restriction, however, while hashes can be nested arbitrarily, only one level of "arrayness" is allowed. Arrays can be usually replaced by hashes, for example instead of having an array of model objects one can have a hash of model objects keyed by their id, an array index or some other parameter.
There's a restriction, however, while hashes can be nested arbitrarily, only one level of "arrayness" is allowed. Arrays can usually be replaced by hashes; for example, instead of having an array of model objects, one can have a hash of model objects keyed by their id, an array index or some other parameter.
WARNING: Array parameters do not play well with the `check_box` helper. According to the HTML specification unchecked checkboxes submit no value. However it is often convenient for a checkbox to always submit a value. The `check_box` helper fakes this by creating an auxiliary hidden input with the same name. If the checkbox is unchecked only the hidden input is submitted and if it is checked then both are submitted but the value submitted by the checkbox takes precedence. When working with array parameters this duplicate submission will confuse Rails since duplicate input names are how it decides when to start a new array element. It is preferable to either use `check_box_tag` or to use hashes instead of arrays.
@ -856,7 +856,7 @@ Or if you don't want to render an `authenticity_token` field:
Building Complex Forms
----------------------
Many apps grow beyond simple forms editing a single object. For example when creating a `Person` you might want to allow the user to (on the same form) create multiple address records (home, work, etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary.
Many apps grow beyond simple forms editing a single object. For example, when creating a `Person` you might want to allow the user to (on the same form) create multiple address records (home, work, etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary.
### Configuring the Model
@ -908,7 +908,7 @@ end
```
The `fields_for` yields a form builder. The parameters' name will be what
`accepts_nested_attributes_for` expects. For example when creating a user with
`accepts_nested_attributes_for` expects. For example, when creating a user with
2 addresses, the submitted parameters would look like:
```ruby