This djangoProject is about important concepts of web development.
all designing procedures , technologies and architectures that will be used in this project are going to be explained in details.
This project is designed for website of a university sport club.
✔️ REST api
✔️ Elastic Search for event filtering and searching
✔️ Postgres Database
✔️ Complete Adming Panel
✔️ suitable reservation system based on calender
✔️ OTP for Authorization
✔️ Push notification
✔️ Message Broker for SOA architecture( in OTP and push notification)
elastic search is a database which is like no sql databases (document based => jason) its archictecture is consist of cluster => nodes =>shards <= indices index => database type => table document => row field => column each index can be spread horizontally in shards each shard is a Lucene index which is the core of story elastic search is relied on Lucene index and elastic search just create a powerful architeture to use Lucene index we have two kinds of shards replica and primary replica is the replacment for primary one in case of emergency each node contains numbers of shards
approaches
1- one index with many types => even one shard is sufficient
2- many index with just one type => it needs more shard to proccess the resault
Another important factor is how you plan to search your data. While each shard is searched independently, Elasticsearch eventually needs to merge results from all the searched shards. For instance if you search across 10 indices that have 5 shards each, the node that coordinates the execution of a search request will need to merge 5x10=50 shard results. Here again you need to be careful: if there are too many shard results to merge and/or if you ran an heavy request that produces large shard responses (which can easily happen with aggregations), the task of merging all these shard results can become very resource-intensive, both in terms of CPU and memory. Again this would advocate for having fewer indices.
to wrap it all you should realize the conditions and needs of your project in order to understand which one should be used
as you see up , in case of indexed documents we have two things an index file(dictionary of words which is used for index) and list of documents we have two approach to work with this files
1- if we know our document we easily choose it from our document list and the dictionary just give us more information about documents => forward indexing
2-we dont know our documents and we use dictionary of words in order to find the documents(searching) =>invert indexing
Example: Your cell phone The forward index in your cell phone is your list of contacts, and which phone numbers (cell, home, work) are associated with those contacts. The inverted index is what allows you to manually enter a phone number, and when you hit "dial" you see the person's name, rather than the number, because your phone has taken the phone number and found you the contact associated with it.
message brokers is used for comminucation of services asynchronously . By message brokers we decoupled our services. In the case of OTP because we need to use it a lot We design a server to connect to it and we just put data on que to be sent to that server and after that by using kaveh negar api( this api is used for sending sms) it sends its messages We could design it by directly call kaveh negar rest api and using async i/o in order not to block thread . But in this way if because of any reason like being offline kaveh negar or being busy kaveh negar we wont miss any request on the other hand we release the presure from our service to another service and we are using microservice architecture
NATS is an open-source, cloud-native, high-performance messaging system. At its core, it’s a Publish/Subscribe (PubSub) system whereby clients can communicate with one another without knowledge of where services are located or what their precise endpoints are. Clients simply publish/subscribe to a subject and NATS takes full responsibility for routing the messages.
Where NATS provides at most once quality of service, streaming adds at least once. Streaming is implemented as a request-reply service on top of NATS.
In other words, Nats Streaming introduces message persistence & message delivery guarantees.
MVC ( Model , View , Controller) is chosen project architecure in order to seperate back and front and use the best of REST api's.
SOA architecutre is chosen for backEnd side.
Service-oriented architecture (SOA) is a type of software design that makes software components reusable using service interfaces that use a common communication language over a network.
A service is a self-contained unit of software functionality, or set of functionalities, designed to complete a specific task such as retrieving specified information or executing an operation. It contains the code and data integrations necessary to carry out a complete, discrete business function and can be accessed remotely and interacted with or updated independently.
In other words, SOA integrates software components that have been separately deployed and maintained and allows them to communicate and work together to form software applications across different systems.
In this project a message broker is used in order to separate requests between various services.
the communications between a computing system are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.
The lowest layer of the OSI Model is concerned with electrically or optically transmitting raw unstructured data bits across the network from the physical layer of the sending device to the physical layer of the receiving device. It can include specifications such as voltages, pin layout, cabling, and radio frequencies. At the physical layer, one might find “physical” resources such as network hubs, cabling, repeaters, network adapters or modems.
At the data link layer, directly connected nodes are used to perform node-to-node data transfer where data is packaged into frames. The data link layer also corrects errors that may have occurred at the physical layer.
The network layer is responsible for receiving frames from the data link layer, and delivering them to their intended destinations among based on the addresses contained inside the frame. The network layer finds the destination by using logical addresses, such as IP (internet protocol). At this layer, routers are a crucial component used to quite literally route information where it needs to go between networks.
The transport layer manages the delivery and error checking of data packets. It regulates the size, sequencing, and ultimately the transfer of data between systems and hosts. One of the most common examples of the transport layer is TCP or the Transmission Control Protocol.
The session layer controls the conversations between different computers. A session or connection between machines is set up, managed, and termined at layer 5. Session layer services also include authentication and reconnections.
The presentation layer formats or translates data for the application layer based on the syntax or semantics that the application accepts. Because of this, it at times also called the syntax layer. This layer can also handle the encryption and decryption required by the application layer.
The Application Layer is topmost layer in the Open System Interconnection (OSI) model. This layer provides several ways for manipulating the data (information) which actually enables any type of user to access network with ease. This layer also makes a request to its bottom layer, which is presentation layer for receiving various types of information from it. The Application Layer interface directly interacts with application and provides common web application services. This layer is basically highest level of open system, which provides services directly for application process.
1- TELNET
2- DNS
3- DHCP
4- SMTP
5- NFS
6- SNMP
7-HTTP
usually working with these protocols is not so easy therefore an interface is use which its name is API ( application programm interface)
imangine servers are like doctors and clieans are patients if you just go to one doctor it is neaded to intoduce yourself to doctor just once and after that you are saved in doctor mind and whenever you go to him its not essential to introduce your self to him(stateful) but if doctor changed all the sates will fucked up and now you should all the staffs again but if you use a state transfer model means a model which transfer all the staff with it self needed no state to be saved it doesnt matter for you changing of doctor because you always transfer your state maybe speed of state transfer is less than others one because each time you need transfer all the states and do the same stuffs in server side but on the other hand it is statelss and if we want to have horizental expandemnt it wont stop
in above example state transfer means it will transfer all of its state on its own. this kind of api uses http therefore it is statelss
sawgger is the implementaion of open api (open api is a specification) It is a IDL(interface definition language) that is used to completly define a restful api You can use YAML JASON to deifne api
an app for storing media in Django this app can help you for saving meida like pictures in any django app it contains all staff that it needs and you can easily install this app on your project and use it ##this is an example use of this app for saving an avatar
avatar = models.ForeignKey(
"storage.MediaModel",
blank=True,
null=True,
on_delete=models.SET_NULL,
related_name="user",
)
avatar = serializers.SerializerMethodField()
class Meta:
model = User
fields = {
"avatar",
}
In this way of using serializers we prevent from circular import because we define a service in storage app that is responsible for serializing it
def get_avatar(self, obj):
if obj.avatar is None:
return None
avatar_id = obj.avatar.id
data = serialize_media_by_id(media_id=avatar_id)
return data