PROTOCOL.md

Client/Server Protocol

General Protocol

The Client may asynchronously send requests to the Server. The Server is expected to return responses as outlined below.

The response must contain at least a [Minimal Response]. Depending on the request, it may provide additional responses as outlined in this section.

Minimal Response

Asynchronous request (read AJAX) initiated by the Client receive a JSON Response from the server containing at least:

{
	"status": "success"|"error",
	"message": "<message>"
}

status indicates whether or not the request has been fullfiled by the server ("success") or encountered an error ("error"). On "error" the Client must display "<message>" to the user. On "success", the Client may display "<message>" to the user.

Depending on the request, the server may provide additional information in the response, as outlined below.

HTML Form Element Validation Response

The Server may perform a serverside validation of values submitted as part of a HTML Form submission. If the validation fails, it may notify the Client by adding following name/value pairs to the response JSON Stream

{
	"status": "error",
	...
    "field-name": "<field name>",
	"field-message": "<message>",
	...
}

Only one validation failure per request can be reported to Client.

The Server is expected to set the status "status" to "error", and the Client is expected to treat the error as explained in [Minimal Response] and must obey the rules of redirection as explained in [Redirection Response].

The Client must visibly highlight the HTML Form Element that caused the validation failure.

"field-name"

The value of the name attribute of the HTML Form Element that caused the validation failure.

"field-message"

Message to the User, indicating the nature of the failure.

Form Group Configuration Response

As part of the server response, the JSON stream may contain a key form-update. This response is used to reconfigure HTML Form Elements and Form Groups on the clientside, based on conditions evaluated on the serverside. It contains an array of objects having the following structure

{
	...
	"form-update" : [
		{
			"form-element": "<element_name>",
			"hidden": true | false,
			"disabled": true | false,
			"required": true | false,
			"value": <value>
		},
		...
	],
	...
}

"form-element"

the name of the HTML Form Element as it appears in the name attribute.

"hidden"

whether the Form Group is visible (value: false) or invisible (value: true).

"disabled"

whether or not the Form Element is disabled HTML-wise.

"required"

whether or not the Form Element receives the HTML5 required attribute.

"value"

For textual HTML Form Input elements, it is supposed to be a scalar value, which is set on the element.When "form-element" references a <select> element, a scalar value selects the corresponding value from the option list. In order to replace the entire option list, use an array of objects as value to "value", having this format

  [
  	...
  	{
  		"value": 100,
  		"text": "a",
  		"selected": true
  	},
  	{
  		"value": 200,
  		"text": "b",
  		"selected": false
  	}
  	...
  ]

"select" is optional, as is "text". If "text" is omitted, it will be derived from value.HTML checkboxes are ticked with a "value" of true. They are unchecked with false.HTML radio buttons are activated by providing the value of the radio button value-attribute to be activated in "value".

Element Configuration Response

As part of the server response, the JSON stream may contain a key element-update. This key stores information on how to modify HTML elements identified by id. Modifying in this context refers to:

• Setting attribute values
• Deleting attributes
• Setting content of a HTML element.

The content of element-update is outlined below

{
    ...
    "element-update" : {
        "<element_id1>": {
            "attr": {
                "<attr_name1>": "<value1>" | null,
                ...
                "<attr_nameN>": "<valueN>" | null
            },
            "content": "<element_content>"
        },
        ...
        "<element_idN>": {
            "attr": {
                "<attr_name1>": "<value1>" | null,
                ...
                "<attr_nameN>": "<valueN>" | null
            },
            "content": "<element_content>"
        }
    },
    ...
}

The presence of element-update is optional. <element_idN> refers to the element's id-attribute value. It used to uniquely identify the HTML element in the DOM. The properties "attr" and "content" are both optional.

Supplying null as value for "<attr_nameN>" will remove the attribute from the HTLM element identified by "<element_idN>".

If the element has no "<attr_nameN>" attribute, the attribute will be created. In any case, the attribute's value will be set to the value specified by "<valueN>". See above for handling of null value.

Redirection Response

Depending on the request, the server may return redirection information to the Client. It is up to the Client to respect the redirection information.

The Client must not perform a redirect in case the status in "status" is "error".

The format of redirect information is outlined below

{
	...
	"redirect": "no" | "url" | "client"
	"redirect-url": "<url>"
	...
}

"redirect"

type of redirection. "no" advises the Client to stay on the Current Page. "client" advises the Client to decide where to redirect to. "url" advices the Client to redirect to the URL provided in "redirect-url".

"redirect-url"

Used to provide an URL when "redirect" is set to "url". It should be disregarded unless "redirect" is set to "url".

API Endpoints

Form Update

The Client may request an updated set of Form Group Configuration and HTLM Element states. In order for the Server to compile the set of Form Group Configuration and HTML Element states, it requires the entire HTML Form in the POST body, without any HTML Input Elements of type file.

The Client must include the SIP using an HTML Input Element (most likely of type hidden).

Request URL

api/load.php

Request Method

POST

URL Parameters

none

Server Response

The response contains at least a [Minimal Response]. In addition, a [Form Group Configuration Response] may be included.

Form Save

The Client submits the HTML Form for persitent storage to the Server. The submission should not contain <input> HTML Elements of type file.

The Client must include the SIP using an HTML Input Element (most likely of type hidden).

Request URL

api/save.php

Request Method

POST

URL Parameters

none

Server Response

The response contains at least a [Minimal Response]. In addition, a [Form Group Configuration Response], [HTML Form Element Validation Response] and/or [Redirection Response] may be included.

File Upload

Files are uploaded asynchronously. Each file to be uploaded requires one request to the Server, using a Multi part form with file content, parameter s containing SIP, and parameter name containing the name of the HTML Form Element.

Request

api/file.php

Request Method

POST

URL Parameters

action=upload

Server Response

The response contains a [Minimal Response].

File Delete

Files are delete asynchronously. Each file to be delete on the serverside requires on request to the Server. The parameters identifying the file to be deleted are sent as part of the POST body. The SIP of the request is included in the parameter name s. The value of the name attribute of the HTML Form Element is provided in name.

Request

api/file.php

Request Method

POST

URL Parameters

action=delete

Server Response

The response contains a [Minimal Response].

Record(s) delete

Request the deletion of the record identified by the SIP. The SIP might contain a SIP_TABLE and/or a SIP_FORM. If both are specified, SIP_FORM will be taken. With SIP_FORM, the tableName is derived from the form.

Request

api/delete.php

Request Method

POST

URL Parameters

s=<SIP>

Server Response

The response contains a [Minimal Response]. [Redirection Response] may be included.

Glossary

SIP

tbd

HTML Form Element

Any <input> or <select> HTML tag. Synonymous to Form Element.

Form Group

The sourrounding <div> containing the .control-label, .form-control <div>s, and .help-block <p>.

Client

Application that enables a user to interact with QFQ, i.e. a Web Browser.

Current Page

The currently displayed page in the Client.

Redirect

Issued by the Server. It is a command prompting the Client to navigate away from the Current Page.