class Yajl::Parser
This class contains methods for parsing JSON
directly from an IO object. The only basic requirment currently is that the IO object respond to read(len) and eof? The IO is parsed until a complete JSON
object has been read and a ruby object will be returned.
Public Class Methods
:symbolize_keys will turn hash keys into Ruby symbols, defaults to false.
:allow_comments will turn on/off the check for comments inside the JSON
stream, defaults to true.
:check_utf8 will validate UTF8 characters found in the JSON
stream, defaults to true.
static VALUE rb_yajl_parser_new(int argc, VALUE * argv, VALUE klass) { yajl_parser_wrapper * wrapper; yajl_parser_config cfg; VALUE opts, obj; int allowComments = 1, checkUTF8 = 1, symbolizeKeys = 0; /* Scan off config vars */ if (rb_scan_args(argc, argv, "01", &opts) == 1) { Check_Type(opts, T_HASH); if (rb_hash_aref(opts, sym_allow_comments) == Qfalse) { allowComments = 0; } if (rb_hash_aref(opts, sym_check_utf8) == Qfalse) { checkUTF8 = 0; } if (rb_hash_aref(opts, sym_symbolize_keys) == Qtrue || rb_hash_aref(opts, sym_symbolize_names) == Qtrue) { symbolizeKeys = 1; } } cfg = (yajl_parser_config){allowComments, checkUTF8}; obj = Data_Make_Struct(klass, yajl_parser_wrapper, yajl_parser_wrapper_mark, yajl_parser_wrapper_free, wrapper); wrapper->parser = yajl_alloc(&callbacks, &cfg, &rb_alloc_funcs, (void *)obj); wrapper->nestedArrayLevel = 0; wrapper->nestedHashLevel = 0; wrapper->objectsFound = 0; wrapper->symbolizeKeys = symbolizeKeys; wrapper->builderStack = rb_ary_new(); wrapper->parse_complete_callback = Qnil; rb_obj_call_init(obj, 0, 0); return obj; }
A helper method for parse-and-forget use-cases
io
is the stream to parse JSON
from
The options
hash allows you to set two parsing options - :allow_comments and :check_utf8
:allow_comments accepts a boolean will enable/disable checks for in-line comments in the JSON
stream
:check_utf8 accepts a boolean will enable/disable UTF8 validation for the JSON
stream
# File lib/yajl.rb, line 43 def self.parse(str_or_io, options={}, read_bufsize=nil, &block) new(options).parse(str_or_io, read_bufsize, &block) end
Public Instance Methods
string_chunk
can be a partial or full JSON
string to push on the parser.
This method will throw an exception if the on_parse_complete
callback hasn’t been assigned yet. The on_parse_complete
callback assignment is required so the user can handle objects that have been parsed off the stream as they’re found.
This callback setter allows you to pass a Proc/lambda or any other object that responds to call.
It will pass a single parameter, the ruby object built from the last parsed JSON
object
static VALUE rb_yajl_parser_set_complete_cb(VALUE self, VALUE callback) { yajl_parser_wrapper * wrapper; GetParser(self, wrapper); wrapper->parse_complete_callback = callback; return Qnil; }
input
can either be a string or an IO to parse JSON
from
buffer_size
is the size of chunk that will be parsed off the input (if it’s an IO) for each loop of the parsing process. 8192 is a good balance between the different types of streams (off disk, off a socket, etc…), but this option is here so the caller can better tune their parsing depending on the type of stream being passed. A larger read buffer will perform better for files off disk, where as a smaller size may be more efficient for reading off of a socket directly.
If a block was passed, it’s called when an object has been parsed off the stream. This is especially usefull when parsing a stream of multiple JSON
objects.
NOTE: you can optionally assign the on_parse_complete
callback, and it will be called the same way the optional block is for this method.
static VALUE rb_yajl_parser_parse(int argc, VALUE * argv, VALUE self) { yajl_status stat; yajl_parser_wrapper * wrapper; VALUE rbufsize, input, blk; unsigned int len; const char * cptr; GetParser(self, wrapper); /* setup our parameters */ rb_scan_args(argc, argv, "11&", &input, &rbufsize, &blk); if (NIL_P(rbufsize)) { rbufsize = INT2FIX(READ_BUFSIZE); } else { Check_Type(rbufsize, T_FIXNUM); } if (!NIL_P(blk)) { rb_yajl_parser_set_complete_cb(self, blk); } if (TYPE(input) == T_STRING) { cptr = RSTRING_PTR(input); len = (unsigned int)RSTRING_LEN(input); yajl_parse_chunk((const unsigned char*)cptr, len, wrapper->parser); } else if (rb_respond_to(input, intern_io_read)) { VALUE parsed = rb_str_new(0, FIX2LONG(rbufsize)); while (rb_funcall(input, intern_io_read, 2, rbufsize, parsed) != Qnil) { cptr = RSTRING_PTR(parsed); len = (unsigned int)RSTRING_LEN(parsed); yajl_parse_chunk((const unsigned char*)cptr, len, wrapper->parser); } } else { rb_raise(cParseError, "input must be a string or IO"); } /* parse any remaining buffered data */ stat = yajl_parse_complete(wrapper->parser); if (wrapper->parse_complete_callback != Qnil) { yajl_check_and_fire_callback((void *)self); return Qnil; } return rb_ary_pop(wrapper->builderStack); }
string_chunk
can be a partial or full JSON
string to push on the parser.
This method will throw an exception if the on_parse_complete
callback hasn’t been assigned yet. The on_parse_complete
callback assignment is required so the user can handle objects that have been parsed off the stream as they’re found.
static VALUE rb_yajl_parser_parse_chunk(VALUE self, VALUE chunk) { yajl_parser_wrapper * wrapper; unsigned int len; GetParser(self, wrapper); if (NIL_P(chunk)) { rb_raise(cParseError, "Can't parse a nil string."); } if (wrapper->parse_complete_callback != Qnil) { const char * cptr = RSTRING_PTR(chunk); len = (unsigned int)RSTRING_LEN(chunk); yajl_parse_chunk((const unsigned char*)cptr, len, wrapper->parser); } else { rb_raise(cParseError, "The on_parse_complete callback isn't setup, parsing useless."); } return Qnil; }