Made room for more case studies
This commit is contained in:
Jonatan Pålsson
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1 changed files with 183 additions and 151 deletions
334
report.lyx
334
report.lyx
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@ -3510,6 +3510,12 @@ and distribution of erlang nodes on physical nodes.
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with third parties are also discussed here.
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with third parties are also discussed here.
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\end_layout
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\end_layout
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\begin_layout Standard
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The chapter ends with case studies of particular features of the GGS.
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The case studies serve as concrete examples of the implementations outlined
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in the rest of this chapter.
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\end_layout
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\begin_layout Section
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\begin_layout Section
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Overview of the prototype
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Overview of the prototype
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\end_layout
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\end_layout
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@ -5583,6 +5589,11 @@ reference "sec:Communication-with-the-GDL-VM"
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.
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.
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\end_layout
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\end_layout
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\begin_layout Standard
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The code which is run in the VM is uploaded to the GGS prior to each game.
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Allowing the clients to upload code allows clients to run any game.
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\end_layout
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\begin_layout Subsection
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\begin_layout Subsection
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The database module
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The database module
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\begin_inset CommandInset label
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\begin_inset CommandInset label
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@ -5701,157 +5712,6 @@ key "webstorage:website"
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interface to the database backend.
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interface to the database backend.
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\end_layout
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\end_layout
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\begin_layout Subsection
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A case study
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\end_layout
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\begin_layout Standard
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So what happens when a client sends a typical game command? Let us look
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at one particular example of a chat client sending the message to change
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the nick of a user (we will discuss a example implementation in JavaScript
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in section
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\begin_inset CommandInset ref
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LatexCommand ref
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reference "sec:Example-of-a-GGS-app"
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\end_inset
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).
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Every communication between modules happens asynchronously, nothing is
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blocking, which is very important in concurrent systems.
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It is probably much easier to follow the steps by following them on
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\begin_inset CommandInset ref
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LatexCommand vref
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reference "fig:The-layout-of"
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\end_inset
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.
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\end_layout
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\begin_layout Enumerate
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Client packages a Game-Command into a package which conforms to the protocol
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structure the GGS is using and sends it over the network
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\end_layout
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\begin_layout Enumerate
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The player module, which is coupled to the TCP-module to react on incoming
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messages accepts the message and forwards the raw data to the protocol
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parser module
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\end_layout
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\begin_layout Enumerate
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The protocol parser parses the message and brings it into the format of
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the internal GGS presentation of such a message, which is just a specialized
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Erlang tuple
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\end_layout
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\begin_layout Enumerate
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The protocol parser sends this Erlang touple back to the player module
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\end_layout
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\begin_layout Enumerate
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The player module checks if it is a Server-Command or a Game-Command.
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In our example it is a Game-Command and it sends the message to the table
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module
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\end_layout
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\begin_layout Enumerate
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The table module sends it to its own Game VM
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\end_layout
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\begin_layout Enumerate
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The Game VM module calls the function
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\emph on
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playerCommand(
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\begin_inset Quotes eld
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\end_inset
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278d5002-77d6-11e0-b772-af884def5349
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\begin_inset Quotes erd
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\end_inset
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,
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\begin_inset Quotes eld
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\end_inset
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nick
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\begin_inset Quotes erd
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\end_inset
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,
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\begin_inset Quotes eld
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\end_inset
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Peter
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\begin_inset Quotes erd
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\end_inset
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)
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\emph default
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within the JavaScript VM
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\end_layout
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\begin_layout Enumerate
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The JavaScript VM (JSVM) - at this stage Googles V8 JavaScript Engine -
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evaluates the function within the sandboxed game context which has been
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established earlier during the setup of the game.
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\end_layout
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\begin_layout Enumerate
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In the example in section
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\begin_inset CommandInset ref
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LatexCommand ref
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reference "sec:Example-of-a-GGS-app"
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\end_inset
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we see that the GGS-functions
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\emph on
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GGS.localStorage.setItem(key, value)
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\emph default
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and
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\emph on
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GGS.localStorage(key)
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\emph default
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are used.
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Both are callbacks coupled to the database module functions.
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\end_layout
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\begin_layout Enumerate
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Data is being read from and written to the database and handed over to the
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JSVM via the database module
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\end_layout
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\begin_layout Enumerate
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In the example the
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\emph on
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GGS.sendCommandToAll()
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\emph default
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is being called then which is a callback to a function of the table module
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which iterates through its player list and sends the command to every player
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\end_layout
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\begin_layout Enumerate
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The table module sends every player instance the message to send the message
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with the change of a nickname of a particular user to its own client.
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\end_layout
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\begin_layout Enumerate
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The player module asks the protocol module to create a message conforming
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to the protocol which is being used
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\end_layout
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\begin_layout Enumerate
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The protocol module creates a string according to the protocol and returns
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it to the player module
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\end_layout
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\begin_layout Enumerate
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The player module sends the message with help of the gen_tcp module to the
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client
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\end_layout
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\begin_layout Section
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\begin_layout Section
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Communication with the GDL VM
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Communication with the GDL VM
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\begin_inset CommandInset label
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\begin_inset CommandInset label
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@ -6689,6 +6549,178 @@ Hot code replacement is a technique used to update systems while they are
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\end_layout
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\end_layout
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\begin_layout Section
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\begin_layout Section
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Case studies
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\end_layout
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\begin_layout Subsection
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Typical communication
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\end_layout
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\begin_layout Standard
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So what happens when a client sends a typical game command? Let us look
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at one particular example of a chat client sending the message to change
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the nick of a user (we will discuss a example implementation in JavaScript
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in section
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\begin_inset CommandInset ref
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LatexCommand ref
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reference "sec:Example-of-a-GGS-app"
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\end_inset
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).
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Every communication between modules happens asynchronously, nothing is
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blocking, which is very important in concurrent systems.
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It is probably much easier to follow the steps by following them on
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\begin_inset CommandInset ref
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LatexCommand vref
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reference "fig:The-layout-of"
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\end_inset
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.
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\end_layout
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\begin_layout Enumerate
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Client packages a Game-Command into a package which conforms to the protocol
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structure the GGS is using and sends it over the network
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\end_layout
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\begin_layout Enumerate
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The player module, which is coupled to the TCP-module to react on incoming
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messages accepts the message and forwards the raw data to the protocol
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parser module
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\end_layout
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\begin_layout Enumerate
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The protocol parser parses the message and brings it into the format of
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the internal GGS presentation of such a message, which is just a specialized
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Erlang tuple
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\end_layout
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\begin_layout Enumerate
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The protocol parser sends this Erlang touple back to the player module
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\end_layout
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\begin_layout Enumerate
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The player module checks if it is a Server-Command or a Game-Command.
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In our example it is a Game-Command and it sends the message to the table
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module
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\end_layout
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\begin_layout Enumerate
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The table module sends it to its own Game VM
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\end_layout
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\begin_layout Enumerate
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The Game VM module calls the function
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\emph on
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playerCommand(
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\begin_inset Quotes eld
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\end_inset
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278d5002-77d6-11e0-b772-af884def5349
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\begin_inset Quotes erd
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\end_inset
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,
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\begin_inset Quotes eld
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\end_inset
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nick
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\begin_inset Quotes erd
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\end_inset
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,
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\begin_inset Quotes eld
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\end_inset
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Peter
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\begin_inset Quotes erd
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\end_inset
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)
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\emph default
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within the JavaScript VM
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\end_layout
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\begin_layout Enumerate
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The JavaScript VM (JSVM) - at this stage Googles V8 JavaScript Engine -
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evaluates the function within the sandboxed game context which has been
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established earlier during the setup of the game.
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\end_layout
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\begin_layout Enumerate
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In the example in section
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\begin_inset CommandInset ref
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LatexCommand ref
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reference "sec:Example-of-a-GGS-app"
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\end_inset
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we see that the GGS-functions
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\emph on
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GGS.localStorage.setItem(key, value)
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\emph default
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and
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\emph on
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GGS.localStorage(key)
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\emph default
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are used.
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Both are callbacks coupled to the database module functions.
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\end_layout
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\begin_layout Enumerate
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Data is being read from and written to the database and handed over to the
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JSVM via the database module
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\end_layout
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\begin_layout Enumerate
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In the example the
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\emph on
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GGS.sendCommandToAll()
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\emph default
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is being called then which is a callback to a function of the table module
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which iterates through its player list and sends the command to every player
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\end_layout
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\begin_layout Enumerate
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The table module sends every player instance the message to send the message
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with the change of a nickname of a particular user to its own client.
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\end_layout
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\begin_layout Enumerate
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The player module asks the protocol module to create a message conforming
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to the protocol which is being used
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\end_layout
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\begin_layout Enumerate
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The protocol module creates a string according to the protocol and returns
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it to the player module
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\end_layout
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\begin_layout Enumerate
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The player module sends the message with help of the gen_tcp module to the
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client
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\end_layout
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\begin_layout Subsection
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Initialization of a game
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\end_layout
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\begin_layout Standard
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\begin_inset Note Note
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status open
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\begin_layout Plain Layout
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Fill this in!
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\end_layout
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\end_inset
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\end_layout
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\begin_layout Subsection
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Example of a GGS server application in JavaScript
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Example of a GGS server application in JavaScript
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\begin_inset CommandInset label
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\begin_inset CommandInset label
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LatexCommand label
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LatexCommand label
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