[PyNodes] How to move custom data over nodes?

Anyone know how to read numpy arrays or even some variables from a socket? I can’t seem to figure out how. I’m trying to change and then read t_value variable from ImageSocket. What am I doing wrong?

ImageSocket class is the socket. ImageInputNode is supposed to write to this socket. ImageViewNode is supposed to read from the socket.

At some point I want to be able to move Numpy classes through the sockets. For now, simple variables would suffice.

class ImageSocket(bpy.types.NodeSocket):    bl_idname = 'ImageSocket'
    bl_label = 'Image Node Socket'

    t_value = "img_sock_0"

    # Optional function for drawing the socket input value
    def draw(self, context, layout, node, text):

    # Socket color
    def draw_color(self, context, node):
        return (0.0, 0.8, 0.0, 0.5)

class ImageEditNodeTree(bpy.types.NodeTree):
    bl_idname = 'ImageTreeType'
    bl_label = 'Image Edit Node Tree'
    bl_icon = 'COLOR'

class ImageInputNode(bpy.types.Node):
    bl_idname = 'ImageInputNodeType'
    bl_label = 'Image Input Node'

    available_objects = []
    for im in bpy.data.images:
        name = im.name
        available_objects.append((name, name, name))

    input_image = bpy.props.EnumProperty(name="", items=available_objects)

    def poll(cls, tree):
        return tree.bl_idname == 'ImageTreeType'

    def draw_buttons(self, context, layout):
        # layout.label("Node settings")
        layout.prop(self, "input_image")

    def init(self, context):
        self.outputs.new('ImageSocket', "image out")

    def update(self):
        self.outputs['image out'].t_value = self.input_image
        print('--'+ repr(self.outputs['image out']))
        # print(self.outputs['image out'])
        # bpy.data.images['generated']

class ImageViewNode(bpy.types.Node):
    bl_idname = 'ImageViewNodeType'
    bl_label = 'Image View Node'

    def poll(cls, tree):
        return tree.bl_idname == 'ImageTreeType'

    def draw_buttons(self, context, layout):
        # print(self.img_name)

    def init(self, context):
        print("node init")
        self.inputs.new('ImageSocket', "image in")
        self.img_name = "init"

    def update(self):
        self.img_name = 'foo'
        if self.inputs['image in'].is_linked and self.inputs['image in'].links[0].is_valid:
            iny = self.inputs['image in'].links[0].from_socket.t_value
            # iny = self.inputs['image in'].default_value
            iny = "error"

import nodeitems_utils
from nodeitems_utils import NodeCategory, NodeItem

class MyNodeCategory(NodeCategory):
    def poll(cls, context):
        return context.space_data.tree_type == 'ImageTreeType'

node_categories = [
    # identifier, label, items list
    MyNodeCategory("IMAGEPNODES", "Image Processing Nodes", items=[
        # our basic node