How mapping works

Example 1

#this mapping script maps an incoming edifact message to a fixed record file.
#bots calls the 'main' function in this mapping script 
def main(inn,out): 
    #inn: the object for the incoming message; via get() and getloop() the content of the message can be accessed. 
    #out: the object for the outgoing message; via put() and putloop() content is written for this message.  
    ordernumber = inn.get({'BOTSID':'UNH'},{'BOTSID':'BGM','1004':None}) #get the order-number. 
                                                                         #The order-number is in field '1004' of record BGM.
                                                                         #Record BGM is nested under record UNH.
    out.put({'BOTSID':'HEA','ORDERNUMBER':ordernumber})                  #put the order-number in the outgoing fixed message, field 'ORDERNUMBER' in record HEA.

    #We first did a get(), than a put(). This can be done in one line:
    out.put({'BOTSID':'HEA','ORDERTYPE':inn.get({'BOTSID':'UNH'},{'BOTSID':'BGM','C002.1001':None})})

    #There can be several dates, all in a DTM record.
    #The 'qualifier' determines the type of date.
    #Fetch the dates like this:
    out.put({'BOTSID':'HEA','ORDERDATE':inn.get({'BOTSID':'UNH'},{'BOTSID':'DTM','C507.2005':'137','C507.2380':None})})     #get statement ONLY looks for DTM with qualifier 137
    out.put({'BOTSID':'HEA','DELIVERY_DATE':inn.get({'BOTSID':'UNH'},{'BOTSID':'DTM','C507.2005':'2','C507.2380':None})})
    #please note: no looping over the DTM-records, just get the data! 

    #The orderlines are in a LIN-recordgroup; so we want each line in its own fixed LIN-record. 
    #start looping the lines (LIN-segments) in the incoming message: 
    for lin in inn.getloop({'BOTSID':'UNH'},{'BOTSID':'LIN'}): 
        #write a fixed LIN record: 
        lou = out.putloop({'BOTSID':'HEA'},{'BOTSID':'LIN'}) 
        #Note: in this loop get() is used on the lin-object, and put() is used for the lou-object!
        lou.put({'BOTSID':'LIN','LINENUMBER':lin.get({'BOTSID':'LIN','1082':None})})
        lou.put({'BOTSID':'LIN','ARTICLE_GTIN':lin.get({'BOTSID':'LIN','C212.7140':None})})
        lou.put({'BOTSID':'LIN','QUANTITY':lin.get({'BOTSID':'LIN'},{'BOTSID':'QTY','C186.6063':'21','C186.6060':None})})

    #OK, we did the lines, but forgot to map the party's - the parties are before the lines in the incoming message. 
    #No problem, get/put can be done anywhere in the mapping - we are NOT looping the incoming or outgoing message:

    out.put({'BOTSID':'HEA','BUYER_ID':inn.get({'BOTSID':'UNH'},{'BOTSID':'NAD','3035':'BY','C082.3039':None})})
    out.put({'BOTSID':'HEA','SUPPLIER_ID':inn.get({'BOTSID':'UNH'},{'BOTSID':'NAD','3035':'SU','C082.3039':None})})
    out.put({'BOTSID':'HEA','DELIVERYPLACE_ID':inn.get({'BOTSID':'UNH'},{'BOTSID':'NAD','3035':'DP','C082.3039':None})})

Mpath: query the edi data

In the examples above the data in the edi messages is queried using eg {'BOTSID':'UNH'},{'BOTSID':'NAD','3035':'BY','C082.3039':None}.
This 'thing' is called a mpath (just a name). Mpath is quite important in building a mapping.

More about mpath:

An mpath consists of one or more python 'dicts' (dictionaries), separated by commas: dict1,dict2, dict3
'BOTSID' is the record identifier.
in get(): 'None' indicates that the value of this field should be returned. All others fields are interpreted as: if field==value.
in put(): all name-values are written, but not if one of the values is 'None'. If one of the values is None no values at all are written to outgoing message. This is used in the combined out.put(...inn.get(...)...)-statements. Detailed information about get, getloop, put, putloop is here

Never do this (use 2 inn.get's in one out.put):

out.put({'BOTSID':'ADD','7747':inn.get('BOTSID':'HEA','name1':None),'7749':inn.get('BOTSID':'HEA','name2':None)})}

Because: if either name1 or name2 is not there (empty, None) nothing will be written in this statement.

Example 2

def main(inn,out):
    #The incoming message object (inn) has a dict 'ta_info'. 
    #ta_info contains information from the QUERIES in the grammar;
    #mostly  envelope data like sender, reciever etc.about the message as specified in the grammar (queries, SUBTRANSLATION). 
    out.put({'BOTSID':'HEA','SENDER':inn.ta_info['frompartner']})

    #The outgoing message object (out) also has a dict ta_info. 
    #You can change it if required. eg. to set topartner:
    BuyerID = inn.get({'BOTSID':'HEA','BUYER_ID':None})
    inn.ta_info['topartner'] = BuyerID       #use BuyerID as topartner (when eveloping)

    #Inn-get() either return a value, or 'None'. Look at the next line:
    out.put({'BOTSID':'UNH'},{'BOTSID':'DTM','C507.2005':'137','C507.2380':inn.get({'BOTSID':'HEA','ORDERDATE':None})})    
    #if there is no ORDERDATE in the HEA record, put() receives a 'None'-value. 
    #Nothing will be written to the outgoing message! 

    #in the next lines 2 values from the inhouse record are written to the same record:
    out.put({'BOTSID':'UNH'},{'BOTSID':'NAD','3035':'DP','C082.3055':'9','C082.3039':inn.get({'BOTSID':'HEA','DELIVERYPLACE_ID':None})})
    out.put({'BOTSID':'UNH'},{'BOTSID':'NAD','3035':'DP','C058.3036':inn.get({'BOTSID':'HEA','DELIVERYPLACE_NAME':None})})
    #both the deliveryplace_id and deliveryplace_name are written to a NAD-record with qualifier 'BY .