Protocol Documentation

Table of Contents

• ServerSideExtension.proto
• BundledRows
• Capabilities
• CommonRequestHeader
• Dual
• Empty
• FieldDescription
• FunctionDefinition
• FunctionRequestHeader
• Parameter
• Row
• ScriptRequestHeader
• TableDescription
• DataType
• FunctionType
• Connector
• Scalar Value Types

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ServerSideExtension.proto

BundledRows

A number of rows collected in one message. The actual number will depend on the size of each row and is adjusted to optimize throughput.

Field	Type	Label	Description
rows	Row	repeated

Capabilities

A full description of the plugin, sent to the Qlik engine, listing all functions available and indicating whether script evaluation is allowed.

Field	Type	Label	Description
allowScript	bool	optional	When true, the Qlik engine allows scripts to be sent to the plugin.
functions	FunctionDefinition	repeated	The definitions of all available functions.
pluginIdentifier	string	optional	The ID or name of the plugin.
pluginVersion	string	optional	The version of the plugin.

CommonRequestHeader

A header sent at the start of both an EvaluateScript request and an ExecuteFunction request under the key "qlik-commonrequestheader-bin".

Field	Type	Label	Description
appId	string	optional	The ID of the app the request was executed in.
userId	string	optional	The ID of the user the request was executed by.
cardinality	int64	optional	The cardinality of the parameters.

Dual

The basic data type for the data stream. Can contain double, string, or both.

Field	Type	Label	Description
numData	double	optional	Numeric value as double.
strData	string	optional	String.

Empty

An empty message used when nothing is to be passed in a call.

Field	Type	Label	Description

FieldDescription

Field definition for function and script calls.

Field	Type	Label	Description
dataType	DataType	optional	The data type of the field.
name	string	optional	The name of the field.
tags	string	repeated	The tags of the field.

FunctionDefinition

The definition of a function, which informs the Qlik engine how to use it.

Field	Type	Label	Description
name	string	optional	The name of the function.
functionType	FunctionType	optional	The type of the function.
returnType	DataType	optional	The return type of the function.
params	Parameter	repeated	The parameters the function takes.
functionId	int32	optional	A unique ID number for the function, set by the plugin, to be used in calls from the Qlik engine to the plugin.

FunctionRequestHeader

A header sent at the start of an ExecuteFunction request under the key "qlik-functionrequestheader-bin".

Field	Type	Label	Description
functionId	int32	optional	The ID of the function to be executed.
version	string	optional	A dummy variable as a workaround for an issue.

Parameter

Parameter definition for functions and script calls.

Field	Type	Label	Description
dataType	DataType	optional	The data type of the parameter.
name	string	optional	The name of the parameter.

Row

A row of duals.

Field	Type	Label	Description
duals	Dual	repeated	Row of duals.

ScriptRequestHeader

A header sent at the start of an EvaluateScript request under the key "qlik-scriptrequestheader-bin".

Field	Type	Label	Description
script	string	optional	The script to be executed.
functionType	FunctionType	optional	The function type of the script evaluation: scalar, aggregation or tensor.
returnType	DataType	optional	The return type from the script evaluation: numeric, string or both.
params	Parameter	repeated	The parameters names and types passed to the script.

TableDescription

A header sent before returning data to Qlik, under the key "qlik-tabledescription-bin".

Field	Type	Label	Description
fields	FieldDescription	repeated	The fields of the table.
name	string	optional	The name of the table.
numberOfRows	int64	optional	Number of rows in table.

DataType

Data types of the parameters and return values.

Name	Number	Description
STRING	0	Contains only string.
NUMERIC	1	Contains only double.
DUAL	2	Contains both a string and a double.

FunctionType

Types of functions (determined by their return values).

Name	Number	Description
SCALAR	0	The return value is a scalar per row.
AGGREGATION	1	All rows are aggregated into a single scalar.
TENSOR	2	Multiple rows in, multiple rows out.

Connector

The communication service provided between the Qlik engine and the plugin.

Method Name	Request Type	Response Type	Description
GetCapabilities	Empty	Capabilities	A handshake call for the Qlik engine to retrieve the capability of the plugin.
ExecuteFunction	BundledRows	BundledRows	Requests a function to be executed as specified in the header.
EvaluateScript	BundledRows	BundledRows	Requests a script to be evaluated as specified in the header.

Scalar Value Types

.proto Type	Notes	C++ Type	Java Type	Python Type
double		double	double	float
float		float	float	float
int32	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead.	int32	int	int
int64	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead.	int64	long	int/long
uint32	Uses variable-length encoding.	uint32	int	int/long
uint64	Uses variable-length encoding.	uint64	long	int/long
sint32	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s.	int32	int	int
sint64	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s.	int64	long	int/long
fixed32	Always four bytes. More efficient than uint32 if values are often greater than $2^{28}$.	uint32	int	int
fixed64	Always eight bytes. More efficient than uint64 if values are often greater than $2^{56}$.	uint64	long	int/long
sfixed32	Always four bytes.	int32	int	int
sfixed64	Always eight bytes.	int64	long	int/long
bool		bool	boolean	boolean
string	A string must always contain UTF-8 encoded or 7-bit ASCII text.	string	String	str/unicode
bytes	May contain any arbitrary sequence of bytes.	string	ByteString	str