This is an example session that shows the some of the types of messages that may be sent between the client, the server, and the kernel.
The user loads http://sagecell.sagemath.org and types the following computation into the browser:
@interact
def f(x=(1, 1000, 1)):
print(factor(x))The user then presses the “Evaluate” button. The client (the browser) sends an HTTP POST request to http://sagecell.sagemath.org/kernel. The following JSON is returned:
{
"kernel_id": "7b3a5b89-7125-4031-b33c-cefd01c8d808",
"ws_url": "ws://sagecell.sagemath.org/"
}The client establishes a WebSocket connection to the URLs ws://sagecell.sagemath.org/kernel/iopub and ws://sagecell.sagemath.org/kernel/shell. These WebSocket connections will act as the IPython IOPub and Shell sockets in the communication with the kernel. If WebSockets are not available, a SockJS connection will be created to the URL http://sagecell.sagemath.org/sockjs, and all messages will be have the prefix 7b3a5b89-7125-4031-b33c-cefd01c8d808/iopub, or 7b3a5b89-7125-4031-b33c-cefd01c8d808/shell,.
The client sends the following message to initiate the computation:
{
"header": {
"msg_id": "37B1EF5AB1A14230BC9251C65E3220C9",
"username": "username",
"session": "313C08D5FC16438E9C35D48771EC74D7",
"msg_type": "execute_request"
},
"metadata": {},
"content": {
"code": "@interact\ndef f(x=(1, 1000, 1)):\n print(factor(x))",
"silent": false,
"user_variables": [],
"user_expressions": {
"_sagecell_files": "sys._sage_.new_files()"
},
"allow_stdin": false
},
"parent_header": {}
}It also sends an HTTP POST request to http://sagecell.sagemath.org/permalink. The request has a parameter called message whose value is
{
"header": {
"msg_type": "execute_request"
},
"metadata": {},
"content": {
"code": "@interact\ndef f(x=(1, 1000, 1)):\n print(factor(x))"
}
}The response to this request is
{
"query": "9da718c3-df3d-4e6a-b20a-6a0b9a655ff5",
"zip": "eJxzyMwrSS1KTC7hSklNU0jTqLDVMNRRMDQwMACSmppWXApAUFAEVKWQBlSVX6RRoQkAjPkOxQ=="
}These values can be used to create the following URLs that serve as permanent links to the computation:
http://sagecell.sagemath.org/?q=9da718c3-df3d-4e6a-b20a-6a0b9a655ff5http://sagecell.sagemath.org/?z=eJxzyMwrSS1KTC7hSklNU0jTqLDVMNRRMDQwMACSmppWXApAUFAEVKWQBlSVX6RRoQkAjPkOxQ==.
The client now listens on the WebSocket connection for messages from the kernel. The client receives the following messages:
{
"parent_header": {
"username": "username",
"msg_id": "37B1EF5AB1A14230BC9251C65E3220C9",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "status",
"msg_id": "de16f9e3-b184-4d31-ba47-34ca0866fa39",
"content": {
"execution_state": "busy"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "de16f9e3-b184-4d31-ba47-34ca0866fa39",
"msg_type": "status"
},
"metadata": {}
}This message tells the client that the kernel is working. When the client receives this message, a spinning icon appears to the user to indicate this status.
{
"parent_header": {
"username": "username",
"msg_id":"37B1EF5AB1A14230BC9251C65E3220C9",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "pyin",
"msg_id": "58116112-3d66-4a9f-b35f-18fa6b2ee155",
"content": {
"execution_count": 1,
"code": "@interact\ndef f(x=(1, 1000, 1)):\n print(factor(x))"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "58116112-3d66-4a9f-b35f-18fa6b2ee155",
"msg_type": "pyin"
},
"metadata": {}
}The kernel echoes the computation to the client. This message is ignored.
{
"parent_header": {
"username": "username",
"msg_id": "37B1EF5AB1A14230BC9251C65E3220C9",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "display_data",
"msg_id": "8b569581-7616-4867-acc0-2d49c6056e28",
"content": {
"source": "sagecell",
"data": {
"application/sage-interact": {
"new_interact_id": "cd552fd2-4caa-4f7c-84a4-6d5842e48a3d",
"layout": {
"top_center": [["x"]]
},
"update": {
"x":["x"]
},
"controls": {
"x": {
"control_type": "slider",
"subtype": "continuous",
"default": 1.0,
"step": 1.0,
"label": null,
"raw": true,
"range": [1.0,1000.0],
"display_value": true
}
}
},
"text/plain": "Sage Interact"
}
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "8b569581-7616-4867-acc0-2d49c6056e28",
"msg_type": "display_data"
},
"metadata": {}
}Add an interact to the output of this computation. This interact has a single control (a slider) and an ID with which its output will be identified.
{
"parent_header": {
"username": "username",
"msg_id": "37B1EF5AB1A14230BC9251C65E3220C9",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "stream",
"msg_id": "170a0ea4-966d-4fa7-8fdc-bda924f7d776",
"content": {
"data": "1\n",
"name": "stdout"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "170a0ea4-966d-4fa7-8fdc-bda924f7d776",
"msg_type": "stream"
},
"metadata": {
"interact_id": "cd552fd2-4caa-4f7c-84a4-6d5842e48a3d"
}
}Print 1 to the output block associated with the interact with the given ID.
{
"parent_header": {
"username": "username",
"msg_id": "37B1EF5AB1A14230BC9251C65E3220C9",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "status",
"msg_id": "68e57f96-537c-410c-a4d4-9b504ce1690b",
"content": {
"execution_state": "idle"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "68e57f96-537c-410c-a4d4-9b504ce1690b",
"msg_type": "status"
},
"metadata": {}
}The kernel has stopped processing. The browser will now hide the spinning icon.
{
"parent_header": {
"username": "username",
"msg_id": "37B1EF5AB1A14230BC9251C65E3220C9",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "execute_reply",
"msg_id": "2a1ef28a-78d6-40e3-8eb8-311ebf79bbe0",
"content": {
"status": "ok",
"execution_count": 1,
"user_variables": {},
"payload": [
{
"new_files": []
}
],
"user_expressions": {
"_sagecell_files": "''"
}
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "2a1ef28a-78d6-40e3-8eb8-311ebf79bbe0",
"msg_type": "execute_reply"
},
"metadata": {
"dependencies_met": true,
"engine": "9ca1c47b-48c6-4c66-b552-d438067ff2db",
"status": "ok",
}
}This message is sent over the Shell channel. It indicates that the computation has completed. If any files were created, they would be reported here.
The user has moved the slider to the value 517. The client sends this message over the shell channel:
{
"header": {
"msg_id": "D90385D5E16445BFA25B18438219F03F",
"username": "username",
"session": "313C08D5FC16438E9C35D48771EC74D7",
"msg_type": "execute_request"
},
"metadata": {},
"content": {
"code": "sys._sage_.update_interact(\"cd552fd2-4caa-4f7c-84a4-6d5842e48a3d\",{\"x\":517})",
"silent": false,
"user_variables": [],
"user_expressions": {
"_sagecell_files": "sys._sage_.new_files()"
},
"allow_stdin": false
},
"parent_header": {}
}
The client receives the following message indicating that the kernel is again busy.
{
"parent_header": {
"username": "username",
"msg_id": "D90385D5E16445BFA25B18438219F03F",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "status",
"msg_id": "86ed02c3-1c38-42f9-9902-deac5cb34fc6",
"content": {
"execution_state": "busy"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "86ed02c3-1c38-42f9-9902-deac5cb34fc6",
"msg_type": "status"
},
"metadata": {}
}{
"parent_header": {
"username": "username",
"msg_id": "D90385D5E16445BFA25B18438219F03F",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "pyin",
"msg_id": "611f1bbc-c0c3-4dc2-9d97-ae0c7557366d",
"content": {
"execution_count": 2,
"code": "sys._sage_.update_interact(\"cd552fd2-4caa-4f7c-84a4-6d5842e48a3d\",{\"x\":517})"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "611f1bbc-c0c3-4dc2-9d97-ae0c7557366d",
"msg_type": "pyin"
},
"metadata": {}
}
The kernel echoes the code through the pyin stream. Again, this message is ignored.
{
"parent_header": {
"username": "username",
"msg_id": "D90385D5E16445BFA25B18438219F03F",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "stream",
"msg_id": "f3997906-85cf-47ef-b72e-ed0d0eb904b0",
"content": {
"data": "11 * 47\n",
"name": "stdout"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "f3997906-85cf-47ef-b72e-ed0d0eb904b0",
"msg_type": "stream"
},
"metadata": {
"interact_id": "cd552fd2-4caa-4f7c-84a4-6d5842e48a3d"
}
}Output 11 * 47 to the output block for this interact.
{
"parent_header": {
"username": "username",
"msg_id": "D90385D5E16445BFA25B18438219F03F",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "status",
"msg_id": "76aca188-3bc9-45f1-9322-3bf6fc17e408",
"content": {
"execution_state": "idle"
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "76aca188-3bc9-45f1-9322-3bf6fc17e408",
"msg_type": "status"
},
"metadata": {}
}The kernel is now idle.
{
"parent_header": {
"username": "username",
"msg_id": "D90385D5E16445BFA25B18438219F03F",
"msg_type": "execute_request",
"session": "313C08D5FC16438E9C35D48771EC74D7"
},
"msg_type": "execute_reply",
"msg_id": "1e1a5cd3-7c39-4efe-b954-422ab80df001",
"content": {
"status": "ok",
"execution_count": 2,
"user_variables": {},
"payload": [
{
"new_files": []
}
],
"user_expressions": {
"_sagecell_files": "''"
}
},
"header": {
"username": "kernel",
"session": "4c12d051-d964-46aa-a635-50bcb3f170ee",
"msg_id": "1e1a5cd3-7c39-4efe-b954-422ab80df001",
"msg_type": "execute_reply"
},
"metadata": {
"dependencies_met": true,
"engine": "9ca1c47b-48c6-4c66-b552-d438067ff2db",
"status": "ok",
}
}The computation has finished.
{
"content": {
"execution_state": "dead"
},
"header": {
"msg_type": "status"
},
"parent_header": {},
"metadata": {}
}After some time, the kernel is killed. This means that no more updates can be sent. (If the “Evaluate” button is pressed again, a new kernel will start.) The client disables the interact controls to indicate this state.