View Source xmerl_xsd (xmerl v2.1)
Interface module for XML Schema validation.
It handles the W3.org specifications of XML Schema second edition 28 october 2004. For an introduction to XML Schema please study part 0.
An XML structure is validated by xmerl_xsd:validate/[2,3].
Summary
Types
The global state of the validator.
Options that allow to customize the behaviour of the validation.
Functions
Read the schema processing state from a file.
Format error descriptions to human readable strings.
Equivalent to process_schema(Schema, []).
Read an XML schema and check that it is valid.
Equivalent to process_schemas(Schemas, []).
Read XML schemas and check that they are valid.
Validate a parsed well-formed XML element towards an XML schema.
Equivalent to state2file(State, SchemaName).
Save the schema processing state to a file.
Equivalent to validate(Element, State, []).
Validate a parsed well-formed XML element (Element).
Types
-type filename() :: string().
-type global_state() :: xsd_state().
The global state of the validator.
It is represented by the #xsd_state{} record.
Options that allow to customize the behaviour of the validation.
Possible options are :
{tab2file,boolean()}- Enables saving of abstract structure on file for debugging purpose.
{xsdbase,filename()}- XSD Base directory.
{fetch_fun,FetchFun}- Call back function to fetch an external resource.
{fetch_path,PathList}- PathList is a list of directories to search when fetching files. If the file in question is not in the fetch_path, the URI will be used as a file name.
{state,State}- It is possible by this option to provide a state with process information from an earlier validation.
Functions
-spec file2state(FileName :: string()) -> {ok, State} | {error, Reason} when State :: global_state(), Reason :: term().
Read the schema processing state from a file.
Reads the schema state with all information of the processed schema from
a file created with state2file/[1,2]. The format of this file is internal.
The state can then be used validating an XML document.
-spec format_error(Reasons) -> io_lib:chars() when Reasons :: [Reason :: term()] | (Reason :: term()).
Format error descriptions to human readable strings.
-spec process_schema(Schema :: string()) -> _.
Equivalent to process_schema(Schema, []).
-spec process_schema(Schema :: string(), Options :: option_list()) -> {ok, State} | {error, Reasons} when State :: global_state(), Reasons :: [Reason :: term()] | (Reason :: term()).
Read an XML schema and check that it is valid.
Reads the referenced XML schema and checks that it is valid. Returns the
global_state/0 with schema info or an error reason. The error reason
may be a list of several errors or a single error encountered
during the processing.
-spec process_schemas(Schemas :: list()) -> _.
Equivalent to process_schemas(Schemas, []).
-spec process_schemas(Schemas, Options) -> {ok, State} | {error, Reasons} when Schemas :: [{NameSpace, Schema}, ...], Options :: option_list(), NameSpace :: term(), Schema :: string(), State :: global_state(), Reasons :: [Reason :: term()] | (Reason :: term()).
Read XML schemas and check that they are valid.
Reads the referenced XML schemas and controls they are valid. Returns the
global_state/0 with schema info or an error reason. The error reason may be
a list of several errors or a single error encountered during the processing.
-spec process_validate(Schema :: string(), Element :: xmerl:element()) -> _.
Equivalent to process_validate(Schema, Element, []).
-spec process_validate(Schema, Element, Options) -> Result when Schema :: string(), Element :: xmerl:element(), Options :: option_list(), Result :: {ValidElement, global_state()} | {error, Reasons}, ValidElement :: xmerl:element(), Reasons :: [Reason :: term()] | (Reason :: term()).
Validate a parsed well-formed XML element towards an XML schema.
Validates in two steps. First it processes the schema, saves the type and structure info in an ETS table and then validates the element towards the schema.
Usage example:
1>{E,_} = xmerl_scan:file("my_XML_document.xml").
2>{E2,_} = xmerl_xsd:process_validate("my_XML_Schema.xsd",E).
Observe that E2 may differ from E if for instance there are default values
defined in my_XML_Schema.xsd.
-spec state2file(State :: global_state()) -> ok | {error, Reason} when Reason :: term().
Equivalent to state2file(State, SchemaName).
SchemaName is the name of the schema in State.
-spec state2file(global_state(), FileName :: string()) -> ok | {error, Reason} when Reason :: term().
Save the schema processing state to a file.
Saves the schema state with all information of the processed schema in a file.
You can provide the file name for the saved state. FileName is saved with the
.xss extension added.
-spec validate(Element :: xmerl:element(), State :: global_state()) -> _.
Equivalent to validate(Element, State, []).
-spec validate(Element, global_state(), Options) -> Result when Element :: xmerl:xmlElement(), Options :: option_list(), Result :: {ValidElement, global_state()} | {error, Reasons}, ValidElement :: xmerl:xmlElement(), Reasons :: [ErrorReason] | ErrorReason, ErrorReason :: term().
Validate a parsed well-formed XML element (Element).
A call to validate/2 or validate/3 must provide a well formed
parsed XML Element :: #xmlElement{}
and a State, global_state/0, which holds necessary information
from an already processed schema. Thus validate enables reuse
of the schema information and therefore if one shall validate
several times towards the same schema it reduces time consumption.
The result, ValidElement, is the valid element that conforms to the
post-schema-validation infoset. When the validator finds an error it tries to
continue and reports a list of all errors found. In those cases an unexpected
error is found it may cause a single error reason.
Usage example:
1>{E,_} = xmerl_scan:file("my_XML_document.xml").
2>{ok,S} = xmerl_xsd:process_schema("my_XML_Schema.xsd").
3>{E2,_} = xmerl_xsd:validate(E,S).Observe that E2 may differ from E if for instance there are default values
defined in my_XML_Schema.xsd.