Class Field

Create a new (generic) field.

'name' -- The name of the field.

'default_value' -- The default value for this field.

'title' -- The name given this field when it is displayed in user interfaces.

'description' -- A string explaining the purpose of this field. The 'description' must be provided as structured text. The first line of the structured text must be a one-sentence description of the field; that line is extracted by 'GetBriefDescription'.

'hidden' -- If true, this field is for internal puprpose only and is not shown in user interfaces.

'read_only' -- If true, this field may not be modified by users.

'computed' -- If true, this field is computed automatically. All computed fields are implicitly hidden and implicitly read-only.

The boolean parameters (such as 'hidden') use the convention that true is represented by the string '"true"'; any other value is false. This convention is a historical artifact.

Overrides: object.__init__

Return a description of this field.

This description is used when displaying detailed help information about the field.

Return a brief description of this field.

This description is used when prompting for input, or when displaying the current value of the field.

Generate help text about this field in HTML format.

'edit' -- If true, display information about editing controls for this field.

Returns the sequence of subfields contained in this field.

returns -- The sequence of subfields contained in this field. If there are no subfields, an empty sequence is returned.

Returns true if this field is computed automatically.

returns -- True if this field is computed automatically. A computed field is never displayed to users and is not stored should not be stored; the class containing the field is responsible for recomputing it as necessary.

Returns true if this 'Field' should be hidden from users.

returns -- True if this 'Field' should be hidden from users. The value of a hidden field is not displayed in the GUI.

Returns true if this 'Field' cannot be modified by users.

returns -- True if this 'Field' cannot be modified by users. The GUI does not allow users to modify a read-only field.

Return a plain text rendering of a 'value' for this field.

'columns' -- The maximum width of each line of text.

returns -- A plain-text string representing 'value'.

Return an HTML rendering of a 'value' for this field.

'server' -- The 'WebServer' in which the HTML will be displayed.

'value' -- The value for this field. May be 'None', which renders a default value (useful for blank forms).

'style' -- The rendering style. Can be "full" or "brief" (both read-only), or "new" or "edit" or "hidden".

'name' -- The name to use for the primary HTML form element containing the value of this field, if 'style' specifies the generation of form elements. If 'name' is 'None', the value returned by 'GetHtmlFormFieldName()' should be used.

returns -- A string containing the HTML representation of 'value'.

Generate a DOM element node for a value of this field.

'value' -- The value to represent.

'document' -- The containing DOM document node.

Validate a field value.

For an acceptable type and value, return the representation of 'value' in the underlying field storage.

'value' -- A value to validate for this field.

returns -- If the 'value' is valid, returns 'value' or an equivalent "canonical" version of 'value'. (For example, this function may search a hash table and return an equivalent entry from the hash table.)

This function must raise an exception if the value is not valid. The string representation of the exception will be used as an error message in some situations.

Implementations of this method must be idempotent.

Parse a value represented as a string.

'value' -- A string representing the value.

returns -- The corresponding field value. The value returned should be processed by 'Validate' to ensure that it is valid before it is returned.

Convert a value submitted from an HTML form.

'request' -- The 'WebRequest' containing a value corresponding to this field.

'name' -- The name corresponding to this field in the 'request'.

'attachment_stores' -- A dictionary mapping 'AttachmentStore' ids (in the sense of Python's 'id' built-in) to the 'AttachmentStore's themselves.

returns -- A pair '(value, redisplay)'. 'value' is the value for this field, as indicated in 'request'. 'redisplay' is true if and only if the form should be redisplayed, rather than committed. If an error occurs, an exception is thrown.

Return a value for this field represented by DOM 'node'.

This method does not validate the value for this particular instance; it only makes sure the node is well-formed, and returns a value of the correct Python type.

'node' -- The DOM node that is being evaluated.

'attachment_store' -- For attachments, the store that should be used.

If the 'node' is incorrectly formed, this method should raise an exception.

Return the form field name corresponding this field.

returns -- A string giving the name that should be used for this field when used in an HTML form.

repr(x)

Overrides: object.__repr__

(inherited documentation)